AP Physics 1 : AP Physics 1

Study concepts, example questions & explanations for AP Physics 1

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Example Questions

Example Question #30 : Impulse And Momentum

A locomotive of mass traveling at couples to a motionless coach without applying the brakes. This took . Determine the average force experienced by the coach.

Possible Answers:

Correct answer:

Explanation:

Use conservation of momentum

Plug in values:

Solve for :

Definition of impulse:

Convert  to

Plug in values:

 

Plug in values

Solve for :

Example Question #491 : Ap Physics 1

A locomotive of mass traveling at couples to a motionless  passenger car without applying the brakes. Assuming no momentum losses, calculate the final velocity.

Possible Answers:

None of these

Correct answer:

Explanation:

Use conservation of momentum

Plug in values:

Solve for :

Example Question #31 : Impulse And Momentum

A tennis player hits an incoming tennis ball of mass  and speed  right back at his opponent at a speed of  in the exact opposite direction. Suppose the collision between the racket and the tennis ball lasted for 

What is the magnitude of the average force exerted by the racket on the tennis ball?

Possible Answers:

Correct answer:

Explanation:

The average force exerted by the racket is related to the impulse by

The impulse is related to the change in momentum by 

 

Equating the two expressions for impulse gives us 

Simplify to get

 

The change in velocity  is given as 

Plugging in this, along with the given change in time and mass of the tennis ball gives us:

Since the question asks for the magnitude of the average force, we get rid of the negative above to obtain 

Example Question #32 : Impulse And Momentum

A car takes to accelerate to from rest. Determine the average force experience by a driver of mass .

Possible Answers:

Correct answer:

Explanation:

Use the equation for momentum:

Initial velocity was

Plug in values:

Example Question #31 : Impulse And Momentum

A popular topic in early space exploration was how to safely return modules back to the surface of the earth. Early designs contained materials that could only withstand impulses of up to  before parts of the module became compromised. One such model of mass 500kg is approaching ocean waters and deploys its shoot, reducing its speed to . If the module decelerates to zero velocity in 0.9 seconds upon hitting the water, is the module structurally compromised?

 

Possible Answers:

No; the impulse experienced is 

Yes; the impulse experienced is 

Yes; the impulse experienced is 

No; the impulse experienced is 

More information is needed to solve

Correct answer:

No; the impulse experienced is 

Explanation:

We need to use the equation for impulse to solve this problem. In fact, the time given is completely irrevelevant:

Plugging in our values:

This is less than the threshold, so no, nothing becomes structurally compromised

Example Question #35 : Impulse And Momentum

An arrow with mass  is shot straight up in the air with an initial kinetic energy of . What is the momentum of the arrow after . Neglect air resistance.

Possible Answers:

Correct answer:

Explanation:

In order to determine the momentum of the arrow, we are going to need its velocity at that time. First, we will convert the initial kinetic energy into initial velocity:

Rearranging for velocity:

Then we can use the following equation to calculate the velocity after 1 second:

Then using the expression for momentum:

Example Question #491 : Ap Physics 1

Conservation of momentum, , is true for which scenario?

Possible Answers:

Momentum is conserved only in one-dimensional collisions.

Momentum is conserved if all forces, , are conservative.

Momentum is always conserved.

Momentum is conserved if no net external force, , is present.

Correct answer:

Momentum is conserved if no net external force, , is present.

Explanation:

Momentum is conserved in isolated systems, (i.e. there are no net external forces.)

Example Question #33 : Impulse And Momentum

Determine the momentum of a baseball of mass  moving at .

Possible Answers:

None of these

Correct answer:

Explanation:

Using the equation for kinetic energy

Converting to and plugging in values:

Example Question #34 : Impulse And Momentum

Two cars of mass hit head on, each traveling at . They then bounce back at If the collision took , determine the magnitude of force experienced by each car.

Possible Answers:

Impossible to determine

None of these

Correct answer:

Explanation:

Using momentum principle:

Since the cars have identical masses and experience the same change in velocity, the forces on them will be identical.

Plugging in values:

Solving for :

Example Question #37 : Impulse And Momentum

Two cars of mass hit head on, each traveling at . They then bounce back at If the collision took , determine the force experienced by a driver of mass in one of the cars.

Possible Answers:

Impossible to determine

None of these

Correct answer:

Explanation:

Using momentum principle:

Since the cars have identical masses and experience the same change in velocity, the forces on them will be identical.

Plugging in values:

Solving for :

Now, determine the acceleration of the car:

Now, determine the force experienced by the driver who was in the car, and thus accelerated with the car.

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