Tra - Level 2 CERT - Tech And Safety

By Spencer Scott
Spencer Scott, Rocketry
Spencer is an Amateur Rocket Hobbyist aiming for TRA Level 2 certification, dedicated to the exhilarating world of rocketry and pushing boundaries in his pursuit
Quizzes Created: 1 | Total Attempts: 180
, Rocketry
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Questions: 108 | Attempts: 180

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Working on my Level 2 cert for TRA


Questions and Answers
  • 1. 

    Which of newton’s laws best describes the behavior of a rocket motor

    • A.

      Newton’s first law: A body continues in its state of rest or of uniform motion in a straight line unless it is compelled to change that state by forces impressed upon it,

    • B.

      Newton’s second law: The rate of change of momentum is proportional to the force impressed and is in the same direction as that force.

    • C.

      Newton’s third law: To every action there is always an equal and opposite reaction.

    Correct Answer
    C. Newton’s third law: To every action there is always an equal and opposite reaction.
    Explanation
    Newton's third law. Applying force in one direction always results in an equal force in an oppssite direction

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  • 2. 

    How does Newton’s third law “to every action there is always an equal and opposite reaction” relate to rocketry?

    • A.

      That the blast deflector must be strong enough to push the rocket off the launch pad at ignition

    • B.

      That a rocket flies because the rocket motor “pushes” the rocket in a direction opposite of the exhaust jet

    • C.

      That the thrust of a rocket motor is proportional to the air density at the launch site

    Correct Answer
    B. That a rocket flies because the rocket motor “pushes” the rocket in a direction opposite of the exhaust jet
    Explanation
    The rocket motor's thrust causes the rocket to accelerate in the direction opposite the motor's thrust. Thus a rocket motor pushes only on the rocket, not on the air or launch pad

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  • 3. 

    What are the three forces action upon a rocket during the course of its flight?

    • A.

      Thrust, Rocket Diameter and finish

    • B.

      Nose cone shape, thrust and drag

    • C.

      Gravity, thrust and aerodynamic drag

    Correct Answer
    C. Gravity, thrust and aerodynamic drag
    Explanation
    Gravity, thrust and drag are the forces acting on a rocket

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  • 4. 

    What are the three major factors that determine the maximum altitude of a high power rocket in vertical flight

    • A.

      Lift-off weight, propellant weight and motor thrust

    • B.

      Fin size, propellant weight and motor thrust

    • C.

      Motor thrust, weight and aerodynamic drag

    Correct Answer
    C. Motor thrust, weight and aerodynamic drag
    Explanation
    The motor thrust, weight and aerodynamic drag are the primary forces considered when determining the altitude of a rocket. Please note that the weight of the rocket must consider the lift-off weight and the weight at burn-out to be complete

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  • 5. 

    For an inherently stable rocket, which statement about the center of gravity (CG) four inches behind the center of pressure (CP). Is this a rocket likely to be stable?

    • A.

      The CG must be behind the CP relative to the desired direction of flight

    • B.

      The CG must be forward of the CP relative to the desired direction of flight

    • C.

      The CG must move forward (in the desired direction of flight) during the motor burn

    Correct Answer
    B. The CG must be forward of the CP relative to the desired direction of flight
    Explanation
    The center of pressure (CP) is where the aerodynamic lift, due to the rocket being at a non-zero angle of attack, is centered. For an aerodynamically stable rocket with the CP behind the center of gravity (CG), the lift which is centered aft of the CG will create a corrective moment to return the rocket to zero degrees angle of attack. Conversely, if the CP is ahead of the CG the lift will attempt to turn the rocket around so that the CP will again be ahead of the CG. This resultant "tumbling" is characteristic of an unstable rocket.

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  • 6. 

    A 4” diameter rocket with its motor is determined to have the center of gravity (CG) four inches behind the center of pressure (CP). Is this rocket likely to be stable?

    • A.

      No, the CG should be at least two body diameters behind the CP

    • B.

      No, the CP must be behind the CG for the rocket to be stable

    • C.

      Yes, the CP is one body diameter in front of the CG

    Correct Answer
    B. No, the CP must be behind the CG for the rocket to be stable
    Explanation
    The rocket is not stable because if the rocket rotated around its center of gravity (CG), the greater aerodynamic force forward of the cg would cause the rocket to rotate even farther, resulting in an unstable flight

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  • 7. 

    The center of pressure (CP) of a rocket is generally defined as:

    • A.

      The balance point of the rocket without the motor

    • B.

      The total area of the fins, airframe and nose cone divided by two

    • C.

      The point at which aerodynamic lift on a rocket is centered

    Correct Answer
    C. The point at which aerodynamic lift on a rocket is centered
    Explanation
    The center of pressure (CP) is the point on the rocket where the aerodynamic lift is centered. This means that aerodynamic lift, if the rocket is at a non-sero angle of attack, forward of this point is balanced by the aerodynamic lift aft of this point.

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  • 8. 

    What is the “rule-of-thumb” for a stable rocket?

    • A.

      That the center of gravity should be at least one body diameter in front of the center of pressure

    • B.

      That the center of gravity should be very nearly at the same point as the center of pressure

    • C.

      The rocket should balance near or at the center of gravity

    Correct Answer
    A. That the center of gravity should be at least one body diameter in front of the center of pressure
    Explanation
    Keeping the center of gravity (CG) one body diameter in front of the center of pressure (CP) typically allows an adaquate margin for rocket stability.

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  • 9. 

    You are at the launch site and decide to fly your rocket on a heavier motor than you simulated it on. Which statement regarding CG is true?

    • A.

      One can install a motor, recovery system and payload and determine the balance point of the rocket as it is ready for flight.

    • B.

      One can balance the rocket with the motor hardware alone because that is the condition of the rocket after motor burnout

    • C.

      It is not necessary to test for the center of gravity when using a heavier motor because it has more thrust

    Correct Answer
    A. One can install a motor, recovery system and payload and determine the balance point of the rocket as it is ready for flight.
    Explanation
    Measuring the center of gravity (CG) by balancing the rocket requires that the rocket be prepared as through ready for flight. It is especially important to check when using heavier motor than previously flown.

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  • 10. 

    What ordinarily happens to the center of gravity (CG) of a rocket during a solid rocket motor’s thrusting phase?

    • A.

      The CG stays the same

    • B.

      The CG shifts forward

    • C.

      The CG shifts aft

    Correct Answer
    B. The CG shifts forward
    Explanation
    As the propellant burns the motor gets lighter and thus moves the balance point of center of gravity (CG) forward. This is why a marginally stable rocket may "act squirrelly" at launch, then stabilize and fly straight.

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  • 11. 

    How can a statically unstable rocket be made stable?

    • A.

      Using a heavier motor

    • B.

      Adding weight to the nose

    • C.

      Making the rocket shorter

    Correct Answer
    B. Adding weight to the nose
    Explanation
    Adding enough weight to the nose will shift the center of gravity (CG) forward of the center of pressure (CP).

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  • 12. 

    What are three methods used to shift center of gravity (CG) of a rocket forward?

    • A.

      Add weight to the nose, make the rocket longer, install the number of fins

    • B.

      Add weight to the nose, make the rocket longer, use a smaller (or lighter) motor

    • C.

      Add weight to the nose, make the rocket shorter, use a smaller motor

    Correct Answer
    B. Add weight to the nose, make the rocket longer, use a smaller (or lighter) motor
    Explanation
    Moving the CG forward requires judicious design changes. The following are given as "rules of thumb": Adding weight to the nose moves the CG forward by counterbalancing the rocket. Think of the rocket as a lever; making the rocket longer shifts the CG forward by making the lever longer. Using a smaller (or lighter) motor reduces the weight aft thus shifting the CG forward.

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  • 13. 

    What are three methods used to shift the center of pressure (CP) aft?

    • A.

      Make the rocket shorter, use larger fins, increase the number of fins

    • B.

      Make the rocket shorter, use smaller fins, add weight to the nose

    • C.

      Make the rocket shorter, change the number of fins, use a longer launch rod

    Correct Answer
    A. Make the rocket shorter, use larger fins, increase the number of fins
    Explanation
    Moving the CP aft requires judicious design changes. The following are give as "rules of thumb": Adding weight to the nose move the CP aft. This can be accomplished by increasing the area on each fin and/or increasing the number of fins. The CP can also shifted aft by maing the rocket shorter. This alone is generally not preferred because the CG is also shifted aft and the CP/CG stability relationship may be compromised.

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  • 14. 

    The definition of coefficient of drag (Cd) is:

    • A.

      A dimensionless number that represents the effect of gravity and Mach number of the rocket

    • B.

      A dimensionless number dependent on the rocket configuration, Mach number and angle of attack

    • C.

      The force, in newton’s, exerted on the rocket by the atmosphere

    Correct Answer
    B. A dimensionless number dependent on the rocket configuration, Mach number and angle of attack
    Explanation
    The correct answer is "A dimensionless number dependent on the rocket configuration, Mach number and angle of attack." This answer accurately describes the definition of the coefficient of drag (Cd). The coefficient of drag is a dimensionless number that represents the resistance or drag experienced by an object moving through a fluid, such as air. It depends on various factors including the shape or configuration of the object (in this case, the rocket), the speed of the object (Mach number), and the angle at which the object is moving through the fluid (angle of attack).

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  • 15. 

    What happens to the coefficient of drag (Cd) as the rocket approaches the speed of sound?

    • A.

      The Cd decreases

    • B.

      The Cd stays the same

    • C.

      The Cd increases

    Correct Answer
    C. The Cd increases
    Explanation
    As the rocket approaches the speed of sound, the coefficient of drag (Cd) increases. This is because at high speeds, the air resistance on the rocket becomes more significant, causing an increase in drag. The Cd is a measure of the aerodynamic efficiency of an object, and as the speed increases, the Cd value also increases. This means that the rocket experiences more air resistance and requires more force to overcome it, making it less efficient in terms of aerodynamics.

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  • 16. 

    For a subsonic rocket, what factors most greatly affect the coefficient of drag (Cd)?

    • A.

      Motor thrust, body diameter, nosecone shape and fin shape

    • B.

      Speed, airframe dimensions, nosecone shape and fin shape

    • C.

      Gravity, airframe dimensions, nosecone shape and fin shape

    Correct Answer
    B. Speed, airframe dimensions, nosecone shape and fin shape
    Explanation
    The coefficient of drag (Cd) is a measure of the resistance an object experiences as it moves through a fluid, in this case, air. In the context of a subsonic rocket, the factors that most greatly affect Cd are speed, airframe dimensions, nosecone shape, and fin shape. Speed affects Cd because as the rocket moves faster, the air resistance increases. Airframe dimensions, nosecone shape, and fin shape also impact Cd as they determine the overall shape and surface area of the rocket, which affects how the air flows around it.

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  • 17. 

    What effect does a boat tail have on a subsonic rocket’s coefficient of drag (Cd)?

    • A.

      No effect, a boat tail is only a cosmetic design feature

    • B.

      It incrases the Cd by changing the airflow over the fins

    • C.

      It decreases the Cd by reducing the base drag

    Correct Answer
    C. It decreases the Cd by reducing the base drag
    Explanation
    A boat tail on a subsonic rocket reduces the base drag, which in turn decreases the coefficient of drag (Cd). Base drag is caused by the pressure difference between the front and rear ends of the rocket, and the boat tail helps to smooth out the airflow and minimize this pressure difference. As a result, the Cd is decreased, improving the rocket's aerodynamic performance.

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  • 18. 

    The flight of a high power rocket can be separated into three portions; they are:

    • A.

      Ignition, burnout and peak altitude

    • B.

      Powered flight, un-powered ascent and peak altitude

    • C.

      Powered flight, un-powered ascent and descent

    Correct Answer
    C. Powered flight, un-powered ascent and descent
    Explanation
    The correct answer is "Powered flight, un-powered ascent and descent". This explanation is based on the understanding of how a high power rocket operates during its flight. During the powered flight phase, the rocket's engines are ignited and provide thrust to propel the rocket upward. Once the engines burn out, the rocket continues to ascend due to its momentum, entering the un-powered ascent phase. Finally, during the descent phase, the rocket descends back to the ground without any active propulsion. Therefore, the flight of a high power rocket can be divided into these three portions.

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  • 19. 

    Which describes the thrust curve of a regressive motor burn?

    • A.

      A high initial thrust relative to the ending thrust of the motor

    • B.

      A lower initial thrust relative to the ending thrust

    • C.

      The thrust curve is flat

    Correct Answer
    A. A high initial thrust relative to the ending thrust of the motor
    Explanation
    A regressive motor burn refers to a type of rocket motor burn where the thrust decreases over time. In this case, the correct answer states that the thrust curve of a regressive motor burn has a high initial thrust relative to the ending thrust of the motor. This means that the motor starts with a strong initial thrust and gradually decreases in thrust as it burns.

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  • 20. 

    Which describes the thrust curve of a progressive motor?

    • A.

      A general decrease in thrust during the burn

    • B.

      A general increase in thrust during the burn

    • C.

      About the same thrust at ignition as at burnout

    Correct Answer
    B. A general increase in thrust during the burn
    Explanation
    A progressive motor is designed to increase its thrust as the burn progresses. This means that as the motor burns, the thrust it produces gradually increases rather than decreases or stays the same. This type of thrust curve allows for a more efficient and controlled acceleration during the burn, making it suitable for applications that require a gradual increase in thrust.

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  • 21. 

    A bates grain has an essentially neutral thrust curve because:

    • A.

      Core burning motors always have a neutral

    • B.

      The area of burning propellant remains relatively constant

    • C.

      The core is centered in the propellant grain

    Correct Answer
    B. The area of burning propellant remains relatively constant
    Explanation
    The correct answer is that the area of burning propellant remains relatively constant. This means that as the propellant burns, the surface area of the burning propellant does not change significantly. This results in a thrust curve that is essentially neutral, meaning that the thrust produced remains relatively constant throughout the burn time. This is in contrast to other types of thrust curves, such as increasing or decreasing thrust curves, where the thrust produced changes significantly over time.

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  • 22. 

    What is the function of the motor liner and the O-ring seals in a solid rocket motor?

    • A.

      To hold all of the parts in place prior to ignition of the rocket motor

    • B.

      To make the motor easier to clean if it is a reloadable motor

    • C.

      To keep the hot gasses of the motor from burning or melting the motor case

    Correct Answer
    C. To keep the hot gasses of the motor from burning or melting the motor case
    Explanation
    The function of the motor liner and the O-ring seals in a solid rocket motor is to keep the hot gases of the motor from burning or melting the motor case. These components act as a barrier, preventing the intense heat and pressure generated during ignition from damaging the structural integrity of the motor case. Without the motor liner and O-ring seals, the motor case would be susceptible to burning or melting, which could lead to catastrophic failure of the rocket motor.

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  • 23. 

    What is the most common oxidizer in commercially available high power composite solid rocket motors?

    • A.

      Ammonium Perchlorate

    • B.

      Ammonium Nitrate

    • C.

      Ammonium Chlorate

    Correct Answer
    A. Ammonium Perchlorate
    Explanation
    Ammonium perchlorate is the most common oxidizer in commercially available high power composite solid rocket motors. It is widely used due to its high oxygen content and stability. Ammonium perchlorate provides the necessary oxygen for the combustion process, allowing the rocket motor to generate thrust. It is a highly effective oxidizer and has been extensively tested and proven to be reliable and safe for use in solid rocket motors.

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  • 24. 

    What is NH4ClO4?

    • A.

      Ammonium Perchlorate

    • B.

      Ammonium Nitrate

    • C.

      Ammonium Chlorate

    Correct Answer
    A. Ammonium Perchlorate
    Explanation
    NH4ClO4 is the chemical formula for Ammonium Perchlorate. It is a white crystalline solid compound that is highly soluble in water. It is commonly used as an oxidizer in rocket propellants, fireworks, and airbag inflators. Ammonium Perchlorate is a strong oxidizing agent and can release oxygen when heated, making it suitable for various pyrotechnic applications.

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  • 25. 

    A small hole is typically drilled near the top of a high power rockets airframe, below the nose cone or payload section. Why?

    • A.

      This hole vents excessive ejection charge pressure, reducing shock cord stress

    • B.

      The hole permits on-board altimeter to obtain air pressure readings

    • C.

      The hole vents internal air pressure as the rocket gains altitude to prevent premature separation

    Correct Answer
    C. The hole vents internal air pressure as the rocket gains altitude to prevent premature separation
    Explanation
    The correct answer is that the hole vents internal air pressure as the rocket gains altitude to prevent premature separation. As the rocket ascends, the air pressure inside the airframe increases. If this pressure is not released, it can cause the rocket to prematurely separate or even explode. By drilling a small hole near the top of the airframe, the excess air pressure can escape, ensuring that the rocket remains intact and stable during flight.

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  • 26. 

    What happens when the injector orifice in an ideal hybrid rocket motor is made smaller (assuming the oxidizer weight stays the same)?

    • A.

      The total impulse decreases and the average thrust increases

    • B.

      The total impulse stays the same and the average thrust increases

    • C.

      The total impulse stays the same and the average thrust decreases

    Correct Answer
    C. The total impulse stays the same and the average thrust decreases
    Explanation
    When the injector orifice in an ideal hybrid rocket motor is made smaller, the total impulse generated by the motor remains the same. However, the average thrust decreases. This is because a smaller injector orifice restricts the flow of oxidizer into the combustion chamber, reducing the amount of propellant available for combustion. As a result, the average thrust produced by the motor decreases.

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  • 27. 

    What happens when the injector orifice in an ideal hybrid rocket motor is increase in diameter (assume the oxidizer weight stays the same)?

    • A.

      The total impulse decreases and the average thrust increases

    • B.

      The total impulse stays the same and the average thrust increases

    • C.

      The total impulse stays the same and the average thrust decreases

    Correct Answer
    B. The total impulse stays the same and the average thrust increases
    Explanation
    When the injector orifice in an ideal hybrid rocket motor is increased in diameter, the total impulse stays the same because the oxidizer weight remains constant. However, the average thrust increases because the larger orifice allows for a greater flow rate of oxidizer, resulting in a higher average thrust.

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  • 28. 

    What is the oxidizer most commonly used in commercial hybrid rocket motor?

    • A.

      N2O

    • B.

      N2O4

    • C.

      NO2

    Correct Answer
    A. N2O
    Explanation
    N2O, also known as nitrous oxide or laughing gas, is the oxidizer most commonly used in commercial hybrid rocket motors. It is preferred due to its stability, ease of handling, and high performance characteristics. N2O is a self-pressurizing oxidizer, meaning it does not require a separate tank or pressurization system. It is also non-toxic and can be stored as a liquid at room temperature, making it a safe and practical choice for commercial applications.

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  • 29. 

    What is the nominal tank pressure of a nitrous oxide hybrid motor at 75F?

    • A.

      100 psi

    • B.

      750 psi

    • C.

      1500 psi

    Correct Answer
    B. 750 psi
    Explanation
    The nominal tank pressure of a nitrous oxide hybrid motor at 75F is 750 psi. This means that the pressure inside the tank is expected to be around 750 pounds per square inch at a temperature of 75 degrees Fahrenheit.

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  • 30. 

    Above what temperature does pressurized nitrous oxide change to a gas?

    • A.

      97 F

    • B.

      75 F

    • C.

      37 F

    Correct Answer
    A. 97 F
    Explanation
    Pressurized nitrous oxide changes to a gas above 97°F.

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  • 31. 

    A rocket with a motor cluster consisting of a central composite motor and four black powder motors, using five identical igniters:

    • A.

      Will result in all motors starting about the same time

    • B.

      Will result in the composite motor starting first followed by the black powder motors

    • C.

      Will result in the black powder motors starting first followed by the central composite motor

    Correct Answer
    C. Will result in the black powder motors starting first followed by the central composite motor
    Explanation
    The correct answer is that the black powder motors will start first followed by the central composite motor. This is because black powder motors typically have a faster ignition time compared to composite motors. Therefore, when the igniters are activated simultaneously, the black powder motors will ignite and start burning before the composite motor.

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  • 32. 

    What typically happens to a marginally stable rocket with a hybrid motor during the thrusting phase?

    • A.

      Nothing

    • B.

      The rocket may become more stable

    • C.

      The rocket may become less stable

    Correct Answer
    C. The rocket may become less stable
    Explanation
    During the thrusting phase, a marginally stable rocket with a hybrid motor may become less stable. This is because the thrust generated by the motor can cause changes in the rocket's center of gravity and center of pressure. If the center of gravity shifts too far forward or if the center of pressure moves rearward, the rocket's stability can be compromised. This can result in increased wobbling or even loss of control during flight.

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  • 33. 

    In general terms, the specific impulse of a rocket motor is:

    • A.

      The total force of the a motor throughout its action time

    • B.

      The total impulse divided by unit weight of propellant

    • C.

      Inversely related to the diameter and length of the propellant grain

    Correct Answer
    B. The total impulse divided by unit weight of propellant
    Explanation
    The specific impulse of a rocket motor is the total impulse divided by the unit weight of the propellant. This means that it measures the efficiency of the rocket motor in terms of how much thrust it can produce per unit of propellant. A higher specific impulse indicates a more efficient motor, as it can generate more thrust for a given amount of propellant.

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  • 34. 

    In general terms, the total impulse of a rocket motor can be described as:

    • A.

      The product of the average motor thrust and burn time

    • B.

      The product of the propellant weight and burn time

    • C.

      The product of the propellant weight and the motor thrust

    Correct Answer
    A. The product of the average motor thrust and burn time
    Explanation
    The correct answer is the product of the average motor thrust and burn time. This is because the total impulse of a rocket motor is determined by how much force the motor produces (thrust) and how long it produces that force (burn time). By multiplying these two values together, we can calculate the total impulse generated by the motor.

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  • 35. 

    The average thrust of a rocket motor is 100 Newtons and the burn time is 4 seconds. What is the total impulse?

    • A.

      25 Newton-seconds

    • B.

      400 Newton-seconds

    • C.

      400 Newtons

    Correct Answer
    B. 400 Newton-seconds
    Explanation
    The total impulse of a rocket motor can be calculated by multiplying the average thrust by the burn time. In this case, the average thrust is given as 100 Newtons and the burn time is 4 seconds. Therefore, the total impulse can be calculated as 100 Newtons * 4 seconds = 400 Newton-seconds.

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  • 36. 

    Which of the motors listed below has the highest total impulse?

    • A.

      J200

    • B.

      J400

    • C.

      K200

    Correct Answer
    C. K200
    Explanation
    The K200 motor has the highest total impulse among the listed motors. Total impulse is a measure of the total energy a motor can produce, and it is calculated by multiplying the average thrust of the motor by the burn time. Since the K200 motor has a higher average thrust and burn time compared to the J200 and J400 motors, it results in a higher total impulse.

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  • 37. 

    Which of the motors listed below has the highest average thrust?

    • A.

      J200

    • B.

      J400

    • C.

      K200

    Correct Answer
    B. J400
    Explanation
    The J400 motor has the highest average thrust among the motors listed.

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  • 38. 

    What is the difference between a J640 and j320 high power rocket motor (assume full 1280 Newton-second J motors)?

    • A.

      The J320 burns out twice as fast as the J640

    • B.

      There is no difference between the motors, the numbers are manufacturer reference only

    • C.

      The J640 burns out twice as fast as the J320

    Correct Answer
    C. The J640 burns out twice as fast as the J320
    Explanation
    The J640 burns out twice as fast as the J320. This means that the J640 motor will reach its burnout point in half the time it takes for the J320 motor to burn out. The burnout time is a measure of how long the motor can sustain its thrust before it exhausts all its propellant. Therefore, the J640 motor will have a shorter burn time compared to the J320 motor.

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  • 39. 

    Which of the following has a total impulse (It) in the J motor range?

    • A.

      It = 600 Newton-seconds

    • B.

      It = 1000 Newton-seconds

    • C.

      It = 1290 Newton-seconds

    Correct Answer
    B. It = 1000 Newton-seconds
    Explanation
    The correct answer is It = 1000 Newton-seconds. This is because the question is asking for the total impulse in the J motor range, and the only option that falls within that range is 1000 Newton-seconds.

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  • 40. 

    What is a Newton?

    • A.

      The amount of force required to accelerate one pound one foot per second per second

    • B.

      The amount of force required to accelerate one kg one foot per second per second

    • C.

      The amount of force required to accelerate one kg one meter per second per second

    Correct Answer
    C. The amount of force required to accelerate one kg one meter per second per second
    Explanation
    A Newton is the amount of force required to accelerate one kg one meter per second per second.

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  • 41. 

    What does the motor designation I220-8 mean?

    • A.

      The motor has between 320-640 N-s impulse, an average thrust of 220 Newtons, with 8 seconds between motor ignition and ejection

    • B.

      The motor has 220 N-s impulse, and average thrust of 220 Newtons, with 8 seconds between the motor burn-out and ejection

    • C.

      The motor has between 320-640 N-s of impulse, an average thrust of 220 Newtons, with 8 seconds between motor burn-out and ejection

    Correct Answer
    C. The motor has between 320-640 N-s of impulse, an average thrust of 220 Newtons, with 8 seconds between motor burn-out and ejection
    Explanation
    The motor designation I220-8 indicates that the motor has an impulse between 320-640 N-s, which refers to the total amount of force exerted by the motor over time. The average thrust of the motor is 220 Newtons, which is the average force exerted by the motor during operation. There is an 8-second delay between the motor burn-out and ejection, indicating the time delay before the motor completely stops functioning and the ejection process begins.

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  • 42. 

    Rocket A is descending at 10 feet per second, rocket B weights the same but is descending at 20 feet per second. Which statement is true?

    • A.

      The two rockets have the same kinetic energy

    • B.

      Rocket B has twice the kinetic energy of rocket A

    • C.

      Rocket B has four times the kinetic energy of rocket A

    Correct Answer
    C. Rocket B has four times the kinetic energy of rocket A
    Explanation
    The kinetic energy of an object is given by the formula KE = 1/2 mv^2, where m is the mass and v is the velocity. Since both rockets have the same mass, the only difference is their velocities. Rocket B is descending at twice the speed of Rocket A, so its velocity is 20 feet per second compared to Rocket A's 10 feet per second. Plugging these values into the formula, we find that Rocket B has four times the kinetic energy of Rocket A.

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  • 43. 

    Rocket A weighs twice as much as rocket B. Both are descending at 20 feet per second. Which statement is true?

    • A.

      The two rockets have the same kinetic energy

    • B.

      Rocket A has twice the kinetic energy of rocket B.

    • C.

      Rocket A has four times the kinetic energy of rocket A

    Correct Answer
    B. Rocket A has twice the kinetic energy of rocket B.
    Explanation
    The kinetic energy of an object is given by the equation KE = 0.5 * m * v^2, where m is the mass of the object and v is its velocity. In this case, Rocket A weighs twice as much as Rocket B, so its mass is twice that of Rocket B. Since both rockets are descending at the same velocity, the velocity term in the equation is the same for both rockets. Therefore, Rocket A has twice the mass of Rocket B, resulting in twice the kinetic energy.

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  • 44. 

    What is the purpose of the launch rod, rail or tower?

    • A.

      To keep the rocket pointing in the right direction prior to flight

    • B.

      To control the rocket’s flight long enough to allow aerodynamic stability

    • C.

      Both a and b

    Correct Answer
    C. Both a and b
    Explanation
    The purpose of the launch rod, rail, or tower is to serve both functions mentioned in options a and b. It keeps the rocket pointing in the right direction before flight, ensuring that it takes off in the desired trajectory. Additionally, it helps control the rocket's flight for a sufficient duration to achieve aerodynamic stability. Therefore, the launch rod, rail, or tower fulfills both purposes simultaneously.

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  • 45. 

    What is the purpose of a launch lug?

    • A.

      To add drag to the rocket at launch

    • B.

      To guide the rocket along the launch rod or rail

    • C.

      Both a and b

    Correct Answer
    B. To guide the rocket along the launch rod or rail
    Explanation
    A launch lug serves the purpose of guiding the rocket along the launch rod or rail. It is a small tube or rod attached to the rocket's body, which slides onto the launch rod or rail during liftoff. This helps to keep the rocket stable and prevents it from veering off course during the initial stages of flight. By ensuring a straight and controlled ascent, the launch lug plays a crucial role in the safe and successful launch of the rocket.

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  • 46. 

    For a cluster rocket, which construction technique will minimize the effect of one motor failing to ignite?

    • A.

      Make the holes in the forward centering ring slightly closer to the rocket’s centerline than those of the aft centering right

    • B.

      Space the centering rings precisely one motor length apart

    • C.

      Use four smaller fins instead of three larger fins

    Correct Answer
    A. Make the holes in the forward centering ring slightly closer to the rocket’s centerline than those of the aft centering right
    Explanation
    By making the holes in the forward centering ring slightly closer to the rocket's centerline than those of the aft centering ring, the effect of one motor failing to ignite can be minimized. This construction technique ensures that the rocket's balance and stability are maintained even if one motor fails to ignite. By shifting the center of gravity slightly towards the centerline, the rocket will be less likely to veer off course or become unstable in the event of a motor failure.

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  • 47. 

    What can happen is all the motors of a cluster do not ignite at launch?

    • A.

      Nothing the rocket is inherently stable

    • B.

      The rocket may not fly straight

    • C.

      The rocket will shred

    Correct Answer
    B. The rocket may not fly straight
    Explanation
    If all the motors of a cluster do not ignite at launch, it can cause the rocket to lose balance and stability. Without the thrust from all motors, the rocket may veer off course and deviate from its intended flight path. This can result in an unstable and unpredictable trajectory, causing the rocket to not fly straight.

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  • 48. 

    What is a shred?

    • A.

      A failure of the rocket air frame during boost resulting in destruction of the rocket

    • B.

      A failure of the recovery system during boost

    • C.

      A failure of the motor causing early ejection

    Correct Answer
    A. A failure of the rocket air frame during boost resulting in destruction of the rocket
    Explanation
    The correct answer is a failure of the rocket air frame during boost resulting in destruction of the rocket. This means that a shred refers to the breaking or tearing apart of the rocket's air frame while it is in the process of boosting. This failure is severe enough to cause the complete destruction of the rocket. It could be due to structural weaknesses, excessive forces, or other factors that cause the rocket's structure to fail under the stress of the boost phase.

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  • 49. 

    What is a cato?

    • A.

      A failure of the rocket resulting in failure of the airframe during boost

    • B.

      A failure of the recovery system during boost

    • C.

      A failure of the motor causing flight termination

    Correct Answer
    C. A failure of the motor causing flight termination
    Explanation
    The correct answer is a failure of the motor causing flight termination. This means that a cato refers to a failure of the rocket motor, which leads to the termination of the flight. It suggests that the motor malfunctioned or experienced a catastrophic failure, causing the rocket to stop functioning and the flight to be terminated.

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  • 50. 

    What is the primary requirement for the rocket motor ignitor?

    • A.

      It must transfer Sufficient heat to the propellant to assure ignition

    • B.

      It must produce hot, high velocity gasses to assure ignition

    • C.

      It must have a high resistance to be reliable

    Correct Answer
    A. It must transfer Sufficient heat to the propellant to assure ignition
    Explanation
    The primary requirement for the rocket motor ignitor is to transfer sufficient heat to the propellant to assure ignition. This is because the ignitor needs to generate enough heat to initiate the combustion process in the propellant, which in turn creates the necessary thrust for the rocket to take off. Without sufficient heat transfer, the propellant may not ignite properly, leading to a failed launch.

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Spencer Scott |Rocketry |
Spencer is an Amateur Rocket Hobbyist aiming for TRA Level 2 certification, dedicated to the exhilarating world of rocketry and pushing boundaries in his pursuit

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Our quizzes are rigorously reviewed, monitored and continuously updated by our expert board to maintain accuracy, relevance, and timeliness.

  • Current Version
  • Mar 21, 2023
    Quiz Edited by
    ProProfs Editorial Team
  • Mar 24, 2015
    Quiz Created by
    Spencer Scott
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