Force Test Review

The picture below shows a student pulling on a rope that is attached to a wall. Which statement correctly describes the amount of force applied by the wall as the student continues to apply a 250-newton force?

• The wall pulls with a force of 125 newtons against the student.

• The wall pulls with a force of 250 newtons against the student.

• The wall exerts twice as much force as the student.

• The wall exerts no force since it is stationary.

Susan gently pushes the tip of her finger against the eraser on her pencil and the pencil does not move. Which of the following figures best illustrates the interaction of forces between Susan's finger and her pencil?

• A

• B

• C

• D

Two students are pushing a cart, as shown below. The cart will move as if it were acted on by a single force with a magnitude of

• 50N

• 150N

• 200N

• 350N

A ball is dropped from the top of a tall building. As the ball falls, the upward force of air resistance becomes equal to the downward pull of gravity. When these two forces become equal in magnitude, the ball will

• flatten due to the forces.

• fall at a constant speed.

• continue to speed up.

• slow to a stop.

A 10-newton force and a 15-newton force are acting from a single point in opposite directions. What additional force must be added to produce equilibrium (a state in which opposing forces are balanced)?

• 5N acting in the same direction as the 10-N force

• 5N acting in the same direction as the 15-N force

• 10N acting in the same direction as the 10-N force

• 25N acting in the same direction as the 15-N force

A 50-kg child on a skateboard experiences a 75-N force as shown. What is the expected acceleration of the child?

• 0.67m/s/s

• 1.50m/s/s

• 6.70m/s/s

• 25.00m/s/s

A soccer player kicks a 0.5-kilogram stationary ball with a force of 50 newtons. What is the force on the player's foot?

• 0N

• 25N

• 50N

• 100N

Automobiles, baseballs, skateboards, and bicycles- the world is full of things that are in motion. Centuries ago the British physicist Sir Isaac Newton stated three laws that describe the ways in which things move. These are Newton's three laws of motion:

The first law: Unless acted upon by an outside force, a body at rest tends to stay at rest, and a body in motion tends to stay in motion.

The second law: Acceleration is equal to the net force acting on a body divided by its mass.

The third law: For every action force there is an equal and opposite reaction force.

A driver starts her car and steps on the gas pedal. The car gradually accelerates to 50km/hr. A few minutes later, the driver suddenly slams on the brakes to avoid hitting a box in the road. As the car comes to a stop, the driver's body appears to launch forward in the seat until it is restrained by the seat belt.

What law best explains why the driver's body appears to launch forward when the brakes are suddenly applied?

• Newton's first law

• Newton's second law

• Newton's third law

• The law of gravity

This computer is sitting at rest on your desk. Which of the following statements best describes this situation?

• There are no forces acting on your computer.

• Your computer is at rest in any coordinate system.

• Your computer exerts no force on the desk.

• There are several forces acting on your computer, but they balance each other.

Use the drawing to answer the following question. All of the boxes shown above can slide easily. Which box will move the farthest if each is struck with the same amount of force?

• the 1-kg box

• the 10-kg box

• the 20-kg box

• the 50-kg box