All AP Physics 1 Resources
Example Questions
Example Question #16 : Impulse And Momentum
A train of mass traveling at strikes a car stuck on the tracks of mass .
Determine the initial momentum of the system.
None
The train and car are our only two objects in the system.
The initial momentum of the car is zero.
So the only momentum that will contribute is that of the train.
Plugging in our values, we get
Example Question #21 : Impulse And Momentum
A train of mass traveling at strikes a car stuck on the tracks of mass . The car becomes stuck on the train.
Determine the final velocity of the train.
None of these
We will need to use conservation of momentum to solve this problem.
Where and refer to the train, and and refer to the car. and refer to the final state of both the train and the car.
Rearranging using algebra......
Plugging in our values, we get .
Example Question #22 : Impulse And Momentum
A train of mass traveling at strikes a car stuck on the tracks of mass . The car becomes stuck on the train.
Determine the final velocity of the car.
None of these
We will need to use conservation of momentum to solve this problem.
Where and refer to the train, and and refer to the car. and refer to the final state of both the train and the car.
Rearranging using algebra......
Plugging in our values, we get .
Example Question #23 : Impulse And Momentum
A train of mass traveling at strikes a car stuck on the tracks of mass .
Let's assume this collison took to happen. That is, it took the car to accelerate to it's new velocity. Determine the force experienced by the car.
None of these
We will need to use conservation of momentum to solve this problem.
Where and refer to the train, and and refer to the car. and refer to the final state of both the train and the car.
Rearranging using algebra......
Plugging in our values, we get .
Then, we will need to find out final momentum of the car.
Since our intial momentum of the car was , our change in momentum will be equal to the .
We will use the definition of impulse, which is the change in momentum:
We will use substitution:
Plugging in our values, we get
Example Question #24 : Impulse And Momentum
A car of mass is accelerated from to in 2s.
Determine the average total forces on this car during this time frame.
Determine the change in the velocity of the car:
Calculate the average acceleration:
Use the definition of force:
Example Question #25 : Impulse And Momentum
A cart is traveling at when it launches a ball straight into the air with initial velocity .
You may ignore air resistance.
How much time will the ball take from the moment it is launched to return to it's initial height?
None of these
First, break the airborne time into two pieces, the ascent and descent.
Ascent:
The ball will need to decelerate from to .
Use acceleration due to gravity.
Solve for
Descent:
Due to parabolic motion, the ball will have the same magnitude of velocity when it returns to it's height as when it launched, albeit in the opposite direction.
Solving for
Add the times together to get the total airtime.
Example Question #26 : Impulse And Momentum
A cart is traveling at when it launches a ball straight into the air with initial velocity . Ignore air resistance.
How far will the cart have traveled by the time the ball returns to it's initial height?
None of these
First, break the airborne time into two pieces, the ascent and descent.
Ascent:
The ball will need to decelerate from to .
Use acceleration due to gravity.
Solve for
Descent:
Due to parabolic motion, the ball will have the same magnitude of velocity when it returns to it's height as when it launched, albeit in the opposite direction.
Solve for
Add the times together.
Multiply the airtime by the velocity of the cart.
Example Question #21 : Impulse And Momentum
An astronaut of mass throws a shot put in space. If the shot put has a magnitude of velocity of in relation to the center of the galaxy, determine the magnitude of velocity of the astronaut in relation to the center of the galaxy.
None of these
Using conservation of momentum:
The initial momentum can be taken as zero from our reference frame.
Plug in values:
Note: The sign of the velocity for the shot put is negative because it will be in the opposite direction as the astronaut. The question is asking for magnitude though, so we know it will be positive regardless of the direction since magnitude does not take into account the direction of motion.
Example Question #28 : Impulse And Momentum
A batter makes contact with a baseball for 0.1 seconds, exerting a constant force of 100 Newtons during the contact.
What is the ball's change in momentum as a result of the contact?
We use the equation:
Where the change in momentum is .
The force, , is and t is the time during which the force is exerted () as given by the problem statement, we plug in to the formula:
Example Question #29 : Impulse And Momentum
A locomotive of mass traveling at couples to a motionless coach without applying the brakes. Calculate the momentum change (the impulse experienced) of the coach.
Use conservation of momentum
Plug in values:
Solve for :
Definition of impulse:
Convert to
Plug in values:
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