AP Quiz Dynamics (friction and incline plane)

The diagram above represents a 10 N block sliding down a 30⁰ incline at a constant speed. What is the force of friction on the block?

• 5.0 N

• 10 N

• 49 N

• 98 N

A block of weight W is pushed against a rough, fixed wall by a force P. The frictional force between the block and the surface is f, and normal force is N. Which of the following diagrams correctly shows all of the forces acting on the block?

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A block of weight W is pushed against a rough, fixed wall by a force P. The frictional force between the block and the surface is f, and normal force is N. The magnitude of the force of friction acting on the block is equal to the magnitude of the force

• P

• W

• N

• N+P

• N-P

An object of mass m is placed on a frictionless inclined plane as shown above. Which of the following expressions represent the normal force on the mass due to the inclined plane?

• mg tan (theta)

• mg cos (theta)

• mg sin (theta)

• mg

An object of mass m is placed on a frictionless inclined plane as shown above. Which of the following expressions represent the acceleration of the mass down the inclined plane?

• g cos(theta)

• mg sin(theta)

• g sin(theta)

• g

What is the gravitational force experienced by a box of mass 50 kg moving down a frictionless plane inclined at 60⁰ angle?

• 9.8 N

• 424 N

• 490 N

• 245 N

An object of mass m = 1 kg is initially placed on a frictionless plane, inclined at 30⁰ as indicated above. How long does it take the mass to move the distance of 10 m down the incline?

• 16 s

• 4 s

• 2 s

• 1 s

Which of the following changes would increase the net acceleration of mass m down the frictionless inclined plane?

• Increasing the mass m

• Releasing the mass in the middle of the inclined plane

• Increasing the length of the incline plane

• Increasing the angle theta

What happens to the acceleration of the block as it moves down a frictionless inclined plane?

• It increases at a negative rate

• It is constant

• It decreases

• It increases at a positive rate