All AP Physics 1 Resources
Example Questions
Example Question #64 : Impulse And Momentum
A man is running at . From that run, he jumps on a resting 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 #71 : Impulse And Momentum
A blob in space of mass is moving in a straight line at . It then collides and sticks to another blob that was previously stationary. The final velocity of the combined blobs is . Find the mass of the second blob.
None of these
Using
Plugging in values:
Example Question #72 : Impulse And Momentum
A ping pong ball is accelerating at . Determine the net force on the ball.
Using
Converting to and plugging in values
Example Question #73 : Impulse And Momentum
A bullet weighing is fired at a velocity of at a block weighing at rest on a frictionless surface. When the bullet hits the block, it becomes lodged in the block and causes the block to move. How fast does the block move after the collision?
Using the equation of momentum,
we can compare the initial and final scenarios and set them equal to each other to solve for the final velocity of the block (don't forget to convert the units of to !):
Example Question #251 : Linear Motion And Momentum
A tennis ball hits a wall head-on with a forward speed of . It rebounds with a speed of . The contact time is . What is the impulse with the wall?
Impulse is defined as a change in momentum:
Pay attention to direction, because this changes the sign!
Example Question #75 : Impulse And Momentum
Force 1 acts on an object for with . Force 2 acts on an object for with .
Which force changes the momentum of the object more?
Force 1
It's impossible to tell.
There is no momentum change in either situation.
Force 1 and Force 2 change the momentum of the object the same amount.
Force 2
Force 1 and Force 2 change the momentum of the object the same amount.
The impulse momentum theorem states:
Where is the change in momentum of an object, is the force acting on the object, and is the amount of time the force acts on the object.
The change in momentum due to Force 1 can be found by:
And the change in momentum due to Force 2 can be found by:
So both situations produce the same change in momentum.
It's important to understand that both force and time have a linear relationship with momentum, meaning that as either force and/or time increase, momentum will also increase.
Example Question #261 : Linear Motion And Momentum
Ball 1 has a mass of a velocity of . Ball 2 has a mass of and a velocity of .
Which ball has the most momentum?
The balls have equivalent momentum.
Ball 2
It's impossible to tell.
Neither ball has any momentum.
Ball 1
The balls have equivalent momentum.
The equation for momentum is given as:
Where is the momentum of an object, is the mass of the object, and is the velocity of the object.
For Ball 1 we have:
For Ball 2 we have:
So the balls have equivalent momentum.
Example Question #71 : Impulse And Momentum
An object has a mass, M, and a velocity, V.
What happens to the objects momentum if its velocity is doubled?
The objects momentum is halved.
The objects momentum remains the same.
The objects momentum goes to zero.
The objects momentum is quadrupled.
The objects momentum doubles.
The objects momentum doubles.
The equation for momentum is given as:
Where is the momentum of an object, is the mass of the object, and is the velocity of the object.
The relationship between momentum and velocity is linear, so when the objects velocity is doubled, its momentum is also doubled.
Example Question #261 : Linear Motion And Momentum
A space shuttle of mass is traveling through space at a velocity of and has gotten slightly off course. What was the impulse if the shuttles velocity is adjusted to ?
We can use the expression for impulse for this problem:
Since we are given the mass and can easily calculate the change in velocity, we'll go with the second form of this expression:
Example Question #261 : Linear Motion And Momentum
A golfer putts a ball away. The ball rolls this distance, never leaving the ground. If the club was swung at , and the coefficient of friction between grass and ball is , how long was the golf club and arm?
Conservation of momentum states that the angular momentum of the golf swing transfers into the linear momentum of the golf ball, or . Since the only forces acting on the ball are kinetic friction and gravity, we can use kinematics to put this equation completely into known quantities.
Solving for gives . Kinematics gives that . Substituting the first expression into the second gives that .
The kinetic friction force can be expressed as and by Newton's second law, . Hence the acceleration due to friction can be written as . Substituting this into our previous kinematic expression finally gives
. Plugging in known values gives . Solving for gives
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