All AP Physics 1 Resources
Example Questions
Example Question #56 : Impulse And Momentum
A spaceship of mass is motionless in space. The rocket is turned on and provides a constant force of . Assume the loss of mass due to spent fuel is negligible.
Determine the acceleration of the ship.
None of these
Plugging in values
Example Question #57 : Impulse And Momentum
A spaceship of mass is motionless in space. The rocket is turned on and provides a constant force of . Assume the loss of mass due to spent fuel is negligible.
Determine the momentum of the ship after .
None of these
Plugging in values
Using
Using
Example Question #58 : Impulse And Momentum
Tom drops a ball of mass from rest from a height . The ball bounces back to a height of . Find the magnitude of the impulse the ground imparted on the ball.
Impulse is just the change in momentum. To find the velocity when the ball hits the ground, we need to use kinematics. We know the height the ball is dropped, the acceleration, and the initial velocity, so we can use the equation . The initial velocity is , , and , so the equation becomes
When the ball bounces back up it reaches a height of . In order to find the velocity immediately after it hits the ground, we can use the same equation with . This will lead it a velocity of
Assuming up is positive, the magnitude of the impulse is just
Example Question #52 : Impulse And Momentum
Two identical rockets are placed on the back of cars. Car has a mass twice that of car . The rockets are identically fired for , then shut off.
How will the momentum of each car compare?
Impossible to determine
None of these
The heavier car has more momentum
They are the same
The lighter car has more momentum
They are the same
Using
Where represents the impulse, which is the change in momentum.
It can be seen that since both cars have the same force applied for equal amount of time, they have identical final momentums.
Example Question #60 : Impulse And Momentum
An object's momentum as a function of time is the following:
, where is some constant.
What is the force of the object (as a function of time) that causes the motion?
Therefore, we simply need to differentiate our momentum equation with respect to time to determine the force.
Example Question #61 : Impulse And Momentum
An object travels for with a force of . For the next , the object travels with a constant force of . What is the change in the momentum for the object in the first ?
Therefore, to find the change in the momentum, we need to sum the force in the various time intervals. Remember, we are only interested in the first , not the entire time stated in the problem.
Example Question #62 : Impulse And Momentum
A truck is driving at relative to the ground. A rocket is launched from the roof backwards at relative to the ground. Determine the final velocity of the truck.
None of these
Using conservation of momentum.
The initial momentum is the combined mass of the truck and the rocket moving together
The final momentum is made up of the momentum of the truck and the rocket, which are now moving in opposite directions
Combining equations
Plugging in values:
Solving for
Example Question #63 : Impulse And Momentum
A man is running at . From that run, he jumps on a skateboard of mass of . Assuming no energy lost to friction, determine the final velocity of the man on the board.
None of these
Using conservation of momentum:
The man and the skateboard are stuck together, and thus become one mass:
Plugging in values:
Solving for
Example Question #64 : Impulse And Momentum
Two wagons are held together with a rope. Lodged between them, is a very powerful spring. The rope is suddenly cut, allowing the spring to launch the wagons. If the first wagon has a mass of , and obtains a maximum velocity of , determine the momentum of the second cart. The second cart has a mass of .
in the opposite direction of the first cart
in the same direction of the first cart
in the same direction of the first cart
None of these
in the opposite direction of the first cart
in the opposite direction of the first cart
Using conservation of momentum.
Since nothing is moving, the initial momentum is zero
The final momentum is made up of the momentum of the two carts
Combining equations
Plugging in values:
Solving for
The negative sign symbolizes that it will move in the opposite direction of the first cart.
Example Question #65 : Impulse And Momentum
Two wagons are held together with a rope. Lodged between them, is a very powerful spring. The rope is suddenly cut, allowing the spring to launch the wagons. If the first wagon has a mass of , and obtains a maximum velocity of , determine the momentum of the second cart. The second cart has a mass of .
in the same direction
in the same direction
in the opposite direction
in the opposite direction
in the opposite direction
in the opposite direction
Using conservation of momentum.
Since nothing is moving, the initial momentum is zero
The final momentum is made up of the momentum of the two carts
Combining equations
Plugging in values:
Solving for
The negative sign symbolizes that it will move in the opposite direction of the first cart.
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