1.
If an object has kinetic energy, then it also must have _____.
Correct Answer
A. Speed
Explanation
If an object has kinetic energy, it means that it is in motion. Speed is a measure of how fast an object is moving, so if an object has kinetic energy, it must also have speed.
2.
An object that has kinetic energy must be _____.
Correct Answer
A. Moving.
Explanation
An object that has kinetic energy must be moving because kinetic energy is the energy possessed by an object due to its motion. If an object is not moving, it does not have any kinetic energy. Therefore, the correct answer is moving.
3.
The formula to calculate work is W= F x d
How much work was done is 5 N of force was used to move an object 25 meters?
Correct Answer
B. 125 Joules
Explanation
The formula to calculate work is W = F x d. In this question, the force used is 5 N and the distance moved is 25 meters. By substituting these values into the formula, we get W = 5 N x 25 m = 125 Joules. Therefore, the correct answer is 125 Joules.
4.
The formula for calculating work = W= F x d
A vehicle at the wrecking yard was pushed forward 7 meters with a force of 5000 N. How much work was done?
Correct Answer
C. 35000 J
Explanation
The formula for calculating work is W = F x d, where W is the work done, F is the force applied, and d is the distance over which the force is applied. In this case, the force applied is 5000 N and the distance over which it is applied is 7 meters. Therefore, the work done can be calculated as W = 5000 N x 7 m = 35000 J.
5.
The formula for calculating work is F x d
A family car ran out of gas in the left lane of a busy street. The father got out of the car and tried to push the car to the gas station. He used about 600 N of force, but the car moved a distance of 0. How much work was done?
Correct Answer
D. 0 J
Explanation
Work is calculated by multiplying the force applied by the distance moved in the direction of the force. In this scenario, the father applied a force of 600 N, but the car did not move any distance. Since the distance moved is 0, the work done is also 0.
6.
According to the definition for work, in order for work to be accomplished their must be a force exerted on an object and
Correct Answer
B. The object must move in the same direction as the applied force
Explanation
According to the definition of work, work is accomplished when a force is exerted on an object and the object moves in the same direction as the applied force. This means that the force and displacement must be in the same direction for work to be done. If the object moves in the opposite direction of the applied force, no work is being done as the force and displacement are in opposite directions. Lifting the object up or moving a distance less than 100 meters are not necessary conditions for work to be accomplished, as long as the force and displacement are in the same direction.
7.
The formula for calculating work is W= F x d
A pulley is used to lift a heavy piano 6 meters up to the second floor. The amount of force applied upward is 700 N. How much work was done?
Correct Answer
B. 4200 J
Explanation
The formula for calculating work is W = F x d, where W represents work, F represents force, and d represents distance. In this scenario, the force applied upward is 700 N and the distance the piano is lifted is 6 meters. Therefore, to calculate the work done, we multiply the force by the distance: W = 700 N x 6 m = 4200 J.
8.
The formula for calculating work is W= F x d
Jerry pulled the library cart 3 meters with a force of 17 N. How much work was done?
Correct Answer
A. 51 J
Explanation
Jerry pulled the library cart 3 meters with a force of 17 N. To calculate the work done, we use the formula W = F x d, where W is the work done, F is the force applied, and d is the distance moved. Plugging in the values, we get W = 17 N x 3 m = 51 J. Therefore, the work done is 51 J.
9.
The formula for calculating work is W= F x d.
A body builder lifts the barbell up 1 meter with a force of 501 N.
Then He uses 501 N to hold the barbell in place for 2 minutes.
How much work was done?
Correct Answer
B. 501 J
Explanation
The work done can be calculated by multiplying the force applied by the distance moved. In the first part, the body builder lifts the barbell up 1 meter with a force of 501 N, so the work done is 501 J. In the second part, the body builder uses the same force of 501 N to hold the barbell in place for 2 minutes. However, since there is no distance moved, no work is done in this case. Therefore, the total work done is 501 J.
10.
The ability to do work or cause change is...
Correct Answer
C. Energy
Explanation
Energy is the correct answer because it is the capacity or ability to do work or cause change. Energy can exist in various forms such as kinetic energy, potential energy, thermal energy, etc. It is essential for any type of work or change to occur, making it a fundamental concept in physics.
11.
The energy an object has while in motion is...
Correct Answer
C. Kinetic energy
Explanation
Kinetic energy is the energy possessed by an object due to its motion. It depends on the mass and velocity of the object. When an object is in motion, it has the ability to do work and transfer energy. Therefore, kinetic energy is the correct answer as it describes the energy an object has while in motion.
12.
Stored energy that results from the position or shape of an object is called...
Correct Answer
A. Potential energy
Explanation
Potential energy is the correct answer because it refers to the stored energy that an object possesses due to its position or shape. This energy has the potential to be converted into other forms of energy, such as kinetic energy, when the object is in motion. Thermal energy refers to the energy associated with the temperature of an object, while kinetic energy is the energy of an object in motion.
13.
Calculate the momentum of a 700g ball that is rolling down a ramp at 4.6m/s.
Correct Answer
A. 3.22 kg x m/s
Explanation
The momentum of an object is calculated by multiplying its mass by its velocity. In this case, the mass of the ball is given as 700g, which is equivalent to 0.7kg. The velocity of the ball is given as 4.6m/s. Multiplying these values together gives a momentum of 3.22 kg x m/s.
14.
If a force of 50N acts on a 5 kg object, its acceleration is equal to ______ meters per second squared.
Correct Answer
D. 10
Explanation
The acceleration of an object can be calculated using the formula a = F/m, where F is the force applied to the object and m is its mass. In this question, the force applied is 50N and the mass of the object is 5 kg. Plugging these values into the formula, we get a = 50N / 5 kg = 10 m/s^2. Therefore, the correct answer is 10.
15.
The resistance an object has to a change in its motion is called ______________,
Correct Answer
B. Inertia
Explanation
Inertia is the resistance an object has to a change in its motion. It is a property of matter that causes objects to continue moving in a straight line at a constant speed or to stay at rest unless acted upon by an external force. Inertia can be thought of as the tendency of an object to resist changes in its state of motion.
16.
3. If a total distance of 750 m is covered in a
time interval of 25 s,the average speed is ______?
Correct Answer
D. 30 m/s
Explanation
The average speed can be calculated by dividing the total distance covered by the time taken. In this case, the total distance covered is 750 m and the time interval is 25 s. Dividing 750 m by 25 s gives us an average speed of 30 m/s.
17.
6. If a person walked at 2 m/s for 12 s he/she
would travel a distance of ________.
Correct Answer
A. 24 m
Explanation
If a person walks at a speed of 2 m/s for 12 seconds, we can calculate the distance traveled by multiplying the speed by the time. Therefore, 2 m/s * 12 s = 24 m.
18.
7. How long would it take to travel 50 km traveling
at a speed of 10 km/hr?
Correct Answer
C. 5 hours
Explanation
At a speed of 10 km/hr, it would take 5 hours to travel 50 km. This can be calculated by dividing the distance (50 km) by the speed (10 km/hr), which gives us 5 hours.
19.
The current in a circuit equals the voltage difference divided by the resistance.
Correct Answer
C. Ohms Law
Explanation
Ohm's Law states that the current flowing through a conductor is directly proportional to the voltage difference across it and inversely proportional to its resistance. In other words, the current in a circuit can be calculated by dividing the voltage difference by the resistance. This relationship is fundamental in understanding and analyzing electrical circuits, and it is named after the German physicist Georg Simon Ohm, who first formulated it. Therefore, Ohm's Law is the correct answer in this case.
20.
The net movement of electric charges in a singe direction.
Correct Answer
B. Electric current
Explanation
Electric current refers to the flow of electric charges in a single direction. It is the movement of electrons through a conductor, such as a wire. This flow of charges is caused by a voltage difference, which creates an electric field that pushes the charges along. Electric circuits, which consist of interconnected components, provide a path for the current to flow. Batteries, as a source of electrical energy, create the voltage difference needed to establish and maintain the electric current in a circuit.
21.
A ____ ____ is related to the force that causes electric charges to flow.
Correct Answer
B. Voltage difference
Explanation
A voltage difference is related to the force that causes electric charges to flow. Voltage difference refers to the potential energy difference between two points in an electric circuit, which creates an electric field that pushes the charges to move. This potential difference is what drives the flow of electric current through a conductor, as charges move from an area of higher voltage to an area of lower voltage. Therefore, the correct answer is "Voltage difference."
22.
Voltage difference is measured in _____.
Correct Answer
C. Volts
Explanation
Voltage difference is measured in volts. Volts is the unit of measurement for voltage, which represents the amount of electric potential difference between two points in an electrical circuit. Amps, electrodes, and centimeters are not appropriate units for measuring voltage difference. Amps measure electric current, electrodes are used in electrical systems, and centimeters measure length or distance.
23.
What is the unit for voltage?
Correct Answer
A. Volts
Explanation
The unit for voltage is volts. Voltage is a measure of the electric potential difference between two points in a circuit. It represents the amount of energy per unit charge that is transferred from one point to another. The volt is named after the Italian physicist Alessandro Volta, who invented the electric battery. It is commonly used in electrical engineering and physics to quantify the strength of an electric field or the potential difference across a circuit component.
24.
What is the unit for current?
Correct Answer
B. Amperes
Explanation
The unit for current is amperes. Amperes is the SI unit for measuring electric current, which is the flow of electric charge in a circuit. It is named after the French physicist André-Marie Ampère, who made significant contributions to the field of electromagnetism. Volts, ohms, and joules are units for voltage, resistance, and energy respectively, and are not used to measure current.
25.
What is the unit for resistance?
Correct Answer
C. Ohms
Explanation
The unit for resistance is ohms. Resistance is a measure of how much a material or device impedes the flow of electric current. It is represented by the symbol Ω and is named after the German physicist Georg Simon Ohm. Volts, amperes, and joules are units of voltage, current, and energy respectively, and are not directly related to resistance.
26.
What is the unit for energy?
Correct Answer
D. Joules
Explanation
The unit for energy is joules. Joules is the standard unit of measurement for energy in the International System of Units (SI). It is named after the English physicist James Prescott Joule, who made significant contributions to the study of energy. Volts, amperes, and ohms are units of measurement for electrical quantities such as voltage, current, and resistance, respectively, but they are not units for energy.
27.
Which of these is the equation for Ohm's Law?
Correct Answer
B. V = IR
Explanation
Ohm's Law states that the voltage (V) across a conductor is directly proportional to the current (I) flowing through it, with the constant of proportionality being the resistance (R) of the conductor. Therefore, the equation V = IR represents Ohm's Law, where V is the voltage, I is the current, and R is the resistance.
28.
What is shown in this picture?
Correct Answer
C. Resistors connected in series
Explanation
The picture shows resistors connected in series. In a series circuit, the components are connected in a single path, one after the other. In this case, the resistors are connected end to end, so the current flows through one resistor before passing through the next. This arrangement increases the total resistance in the circuit, as the resistances add up.
29.
Why can birds sit on a power line?
Correct Answer
D. Because both feet are on the same voltage line, so there is no potential difference, so current does not flow through the bird
Explanation
Birds can sit on a power line because both of their feet are on the same voltage line. This means that there is no potential difference between the bird's feet, which prevents the flow of current through the bird.
30.
A certain steam iron carries a current of 6.4 A when connected to a 120 V source. What is the resistance of the steam iron?
Correct Answer
D. 18.75 Ω
Explanation
When a steam iron is connected to a 120 V source and carries a current of 6.4 A, we can use Ohm's Law to calculate the resistance. Ohm's Law states that resistance (R) is equal to voltage (V) divided by current (I). Therefore, the resistance of the steam iron can be calculated as 120 V divided by 6.4 A, which equals 18.75 Ω.
31.
The resistance of a hotplate is 48 Ω . How much current does the plate carry when connected to a 120-V source?
Correct Answer
B. 2.5 A
Explanation
The current flowing through a circuit can be calculated using Ohm's Law, which states that current (I) is equal to voltage (V) divided by resistance (R). In this case, the voltage is 120 V and the resistance is 48 Ω. Therefore, the current flowing through the hotplate can be calculated as 120 V / 48 Ω = 2.5 A.
32.
Voltage is a measurement of what?
Correct Answer
C. Potential energy stored in a battery
Explanation
Voltage is a measurement of potential energy stored in a battery. Voltage represents the amount of electric potential energy per unit charge available in a circuit. It is a measure of the force or pressure that pushes electric charges to move in a circuit. In the case of a battery, voltage is the potential energy difference between the positive and negative terminals, which drives the flow of electrons through the circuit. Therefore, the correct answer is potential energy stored in a battery.
33.
What is current?
Correct Answer
A. The flow of charges, usually in the form of electrons
Explanation
Current is defined as the flow of electric charges, typically in the form of electrons. It refers to the movement of charged particles through a conductor, such as a wire. The flow of these charges creates an electric current, which can be measured in units of amperes.
34.
A cyclist accelerates from rest to 12m/s in 4s. His acceleration is:-
Correct Answer
B. 3m/s2
Explanation
The cyclist accelerates from rest to 12m/s in 4s. Acceleration is defined as the change in velocity divided by the time taken. In this case, the change in velocity is 12m/s (final velocity) minus 0m/s (initial velocity), which equals 12m/s. Dividing this by the time taken of 4s gives an acceleration of 3m/s2.
35.
A car accelerates at 6m/s2 for 4s. If it starts at rest its final speed is:-
Correct Answer
A. 24m/s
Explanation
The car accelerates at a constant rate of 6m/s^2 for 4 seconds. To find the final speed, we can use the formula v = u + at, where v is the final velocity, u is the initial velocity (which is 0 in this case), a is the acceleration, and t is the time. Plugging in the values, we get v = 0 + 6(4) = 24m/s. Therefore, the correct answer is 24m/s.
36.
An aircraft on the runway accelerates at 8m/s2 from rest until it reaches its take-off speed of 60m/s. How long does it take to reach this speed?
Correct Answer
D. 5s
Explanation
The aircraft accelerates at a constant rate of 8m/s2. To find the time it takes to reach the take-off speed of 60m/s, we can use the formula: time = (final velocity - initial velocity) / acceleration. Plugging in the values, we get: time = (60m/s - 0m/s) / 8m/s2 = 7.5s. Therefore, the correct answer is 5s.
37.
A motor cyclist does an emergency stop when he is travelling at 36m/s. If the motorcycle stops in 3s what is his deceleration?
Correct Answer
E. 12m/s2
Explanation
The deceleration of the motorcyclist can be calculated using the formula: acceleration = (final velocity - initial velocity) / time. In this case, the initial velocity is 36m/s, the final velocity is 0m/s (since the motorcycle stops), and the time is 3s. Plugging these values into the formula, we get: acceleration = (0m/s - 36m/s) / 3s = -36m/s / 3s = -12m/s2. The negative sign indicates deceleration. Therefore, the correct answer is 12m/s2.
38.
A parachutist opens her parachute at an altitude of 1000m when she is travelling at 48m/s. The parachute causes her to decelerate at 4m/s2 for 8s. At what speed does she continue towards the ground?
Correct Answer
C. 12m/s
Explanation
The parachutist opens her parachute at an altitude of 1000m and is initially traveling at a speed of 48m/s. The parachute causes her to decelerate at a rate of 4m/s^2 for 8 seconds. To find her final speed, we can use the equation: final speed = initial speed - (acceleration * time). Plugging in the values, we get: final speed = 48m/s - (4m/s^2 * 8s) = 48m/s - 32m/s = 16m/s. Therefore, the correct answer is 12m/s.
39.
The key difference between velocity and speed is:-
Correct Answer
E. Velocity is used when the direction matters.
Explanation
The correct answer is "velocity is used when the direction matters." In physics, velocity is a vector quantity that includes both speed and direction. Speed, on the other hand, is a scalar quantity that only measures how fast an object is moving without considering the direction. Therefore, velocity is used when the direction of motion is important, while speed can be used regardless of the direction.
40.
A car travelling at a constant speed around a roundabout is accelerating because:-
Correct Answer
D. The car is changing direction
Explanation
The correct answer is "The car is changing direction." When a car is traveling around a roundabout, it is constantly changing its direction of motion. Even though the car may be maintaining a constant speed, its velocity is changing because velocity is a vector quantity that takes into account both speed and direction. Therefore, the car is accelerating because it is experiencing a change in its velocity, specifically in its direction.
41.
The units of acceleration are:-
Correct Answer
C. Metres per second squared
Explanation
The units of acceleration are measured in meters per second squared. This is because acceleration is defined as the rate of change of velocity over time. Velocity is measured in meters per second, and when it changes over time, the unit becomes meters per second squared. This unit represents how much the velocity changes per second, indicating the rate at which an object's speed or direction is changing.
42.
If an object is moving at a constant velocity, the forces on it are:-
Correct Answer
C. Balanced
Explanation
If an object is moving at a constant velocity, it means that the object is not accelerating. According to Newton's first law of motion, an object will continue to move at a constant velocity unless acted upon by an external force. Therefore, if the object is not accelerating, it must be experiencing balanced forces. Balanced forces occur when the forces acting on an object are equal in magnitude and opposite in direction, resulting in a net force of zero.
43.
If a bicycle and rider of mass 80kg is accelerating at 1.5m/s^{2 }the force pushing it is:-
Correct Answer
C. 120N
Explanation
When a bicycle and rider are accelerating, there is a force acting on them in the direction of the acceleration. According to Newton's second law of motion, the force can be calculated by multiplying the mass of the bicycle and rider (80kg) by the acceleration (1.5m/s^2). Therefore, the force pushing the bicycle and rider is 120N.
44.
A lorry accelerates at 6m/s^{2} when the engine provides a resultant force of 48kN. What is the mass of the lorry?
Correct Answer
E. 8000kg
Explanation
The mass of an object can be calculated using Newton's second law of motion, which states that force is equal to mass multiplied by acceleration. In this case, the given resultant force is 48kN and the acceleration is 6m/s^2. Rearranging the formula, we have mass = force/acceleration. Substituting the values, we get mass = 48,000N / 6m/s^2 = 8,000kg. Therefore, the mass of the lorry is 8000kg.
45.
A motorcyclist of mass 250kg accelerates from rest to 20m/s in 4s. What is the force from the engine?
Correct Answer
A. 1250N
Explanation
The force from the engine can be determined using Newton's second law of motion, which states that force is equal to mass multiplied by acceleration. In this case, the mass of the motorcyclist is given as 250kg and the acceleration can be calculated by dividing the change in velocity (20m/s) by the time taken (4s). Therefore, the acceleration is 5m/s². By substituting the values into the formula, the force from the engine is calculated as 250kg * 5m/s² = 1250N.
46.
A seatbelt brings a passenger to a stop from 12m/s in just 2s. If the passenger has a mass of 60kg, what is the force exerted by the seatbelt?
Correct Answer
B. 360N
Explanation
When a passenger wearing a seatbelt comes to a stop, the force exerted by the seatbelt can be calculated using Newton's second law of motion, which states that force is equal to mass multiplied by acceleration. In this case, the acceleration can be determined by dividing the change in velocity (12m/s) by the time taken (2s), resulting in an acceleration of 6m/s^2. Therefore, the force exerted by the seatbelt can be calculated by multiplying the mass of the passenger (60kg) by the acceleration (6m/s^2), which equals 360N.
47.
Which graph represents a car with positive acceleration?
Correct Answer
A. A
Explanation
Graph A represents a car with positive acceleration because the velocity of the car is increasing over time. The slope of the graph is positive, indicating that the car is gaining speed.
48.
An inflated balloon which has been rubbed against a person's hair is touched to a neutral wall and remains attracted to it. Which diagram best represents the charge distribution on the balloon and wall?
Correct Answer
C. Option 3
Explanation
Option 3 best represents the charge distribution on the balloon and wall. When the balloon is rubbed against a person's hair, it becomes negatively charged due to the transfer of electrons. The neutral wall, on the other hand, remains neutral. The negative charge on the balloon attracts positive charges on the wall, causing the balloon to stick to the wall. Option 3 shows a negatively charged balloon and positive charges on the wall, indicating the attraction between them.
49.
The force of repulsion or attraction between the poles of a magnet is called__________.
Correct Answer
C. Margentic force.
Explanation
The force of repulsion or attraction between the poles of a magnet is called magnetic force. This force is responsible for the interaction between magnets and other magnetic materials. It is the result of the magnetic field that surrounds a magnet and exerts a push or pull on other magnets or magnetic objects.
50.
A material through which heat or electricity do not flow easily
Correct Answer
C. Insulator
Explanation
An insulator is a material that does not allow the easy flow of heat or electricity. Unlike conductors, which allow the flow of heat or electricity, insulators have high resistance and prevent the transfer of energy. This property makes insulators useful for electrical insulation and thermal insulation, as they can protect against electrical shocks and prevent heat loss or gain. Examples of insulators include rubber, plastic, glass, and wood.