AP Physics Forces and Newtons laws

The Earth pulls downward on a pingpong ball with a force  of 1N. If this is the "action" force, what is the "reaction" force?

• The ground exerts a force of 1N on the ping pong ball
• The ping pong ball exerts a force of 1 N on the Earth
• The ping pong ball pushes down on the earth with a force of 1N
• The is no reaction force when a gravitational force is involved

Given the FBD, which of the following must be true?

• The frictional force must be accelerating the system to the left.

• The box must be accelerating to the right.

• The box must be moving to the right.

• The FBD is incorrectly drawn. This situation isn't possible

Which of the following is true about the system shown?

• The system is not accelerating.
• The tension between m₂ and m₁ is less than the tension between m₂ and m₃
• The acceleration of the system only depends on m₃
• None of the other answers are true

Camille launches has a catapult that changes the velocity of a ball (m= 2 kg) from 0 to 10 m/s in one sec. What is the average force that is exerted on the ball during launch?

• 20 N

• 5 N

• 8 N

• 0.2 N

Which of the following statements is true about the image above?

• The accelerations of the blocks will vary according to their mass

• The net force acting on each block is the same

• The blocks will experience the same acceleration

• The 3m box will eat the 2m and the m boxes

Which of the following is not true about the system?

• T₃ is equal to the scalar sum of the magnitudes of T₂ and T₁

• T₃ is equal in magnitude to F_g

• The x- components of the T₁ and T₂ and equivalent but in opposite directions

• The system is in equilibrium.

Sam is hover boarding down they hall at a constant velocity. Assuming there is friction, which of the following must be true?

• The force applied by the board must be greater than the frictional force

• The frictional force must equal the force applied by the board

• The force applied must equal zero

• There is not enough information

If there is no friction, then the acceleration would be equal to

• mg

• sin(θ)mg

• g

• sin(θ)g

If μ_k = 0.65 and μ_s = 0.7, acceleration would be equal to

• 0 m/s/s

• 9.8 m/s/s

• 3.35 m/s/s

• -2.63 m/s/s

What is the coefficient of static friction if it takes 44 N of force to move a box that weighs 86 N? 

• 0.78
• 0.51
• 0.78 N
• 0.58 N