Tra - Level 2 CERT - Tech And Safety

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,

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.

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

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

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

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

Thrust, Rocket Diameter and finish

Nose cone shape, thrust and drag

Gravity, thrust and aerodynamic drag

Lift-off weight, propellant weight and motor thrust

Fin size, propellant weight and motor thrust

Motor thrust, weight and aerodynamic drag

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

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

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

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

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

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

The balance point of the rocket without the motor

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

The point at which aerodynamic lift on a rocket is centered

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

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

The rocket should balance near or at the center of gravity

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

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

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

The CG stays the same

The CG shifts forward

The CG shifts aft

Using a heavier motor

Adding weight to the nose

Making the rocket shorter

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

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

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

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

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

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

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

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

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

The Cd decreases

The Cd stays the same

The Cd increases

Motor thrust, body diameter, nosecone shape and fin shape

Speed, airframe dimensions, nosecone shape and fin shape

Gravity, airframe dimensions, nosecone shape and fin shape

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

It incrases the Cd by changing the airflow over the fins

It decreases the Cd by reducing the base drag

Ignition, burnout and peak altitude

Powered flight, un-powered ascent and peak altitude

Powered flight, un-powered ascent and descent

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

A lower initial thrust relative to the ending thrust

The thrust curve is flat

A general decrease in thrust during the burn

A general increase in thrust during the burn

About the same thrust at ignition as at burnout

Core burning motors always have a neutral

The area of burning propellant remains relatively constant

The core is centered in the propellant grain

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

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

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

Ammonium Perchlorate

Ammonium Nitrate

Ammonium Chlorate

Ammonium Perchlorate

Ammonium Nitrate

Ammonium Chlorate

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

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

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