What is a free-body diagram?

• A diagram of the human body

• A picture or sketch used to show the vectors acting on an object, with arrows representing them

• A picture or sketch used to show the fields near an object, with arrows representing the fields

• A picture or sketch used to show the forces acting on an object, with arrows representing the forces

Which one of the following free-body diagrams depicts an object accelerating to the right?

• Diagram A

• Diagram B

• Diagram C

• Diagram D

The free-body diagram (FBD) shown illustrates the forces acting on an object and the resulting net force. Which set of forces would correctly produce the net force indicated in the diagram?

• A = 0 N; B = 0 N

• A = 50 N; B = 200 N

• A = 100 N; B = 100 N

• A = 200 N; B = 200 N

What is inertia?

• The force of gravity on an object.

• The amount of matter in an object.

• The amount of force acting on each kilogram of mass.

• The tendency of an object to resist changes in its state of motion.

Which of the following is a statement of Newton's First Law of Motion?

• Acceleration varies directly with the unbalanced force.

• If no net force acts on an object, the object maintains its state of motion.

• For every action force, there exists a reactive force that is equal in magnitude but opposite in direction.

• If no unbalanced force acts on an object, the object accelerates in the direction of the single greatest force acting on the object.

A student pushes a heavy cabinet, but it does not move. Which statement is most accurate?

• The applied push is balanced by the opposing forces, so the net force is zero.

• The cabinet has no inertia at rest; inertia only appears when the object is already moving.

• Friction is completely absent in this situation, so only gravity prevents motion of the cabinet.

• Newton’s Second Law is violated because an applied force should always cause motion in real situations.

A person tries to slide a chair, but it doesn’t move. Then he pushes harder and the chair suddenly starts sliding. Which force was overcome?

• Gravity

• Kinetic friction

• Normal force

• Static friction

You push a crate across a rough floor at constant speed. Which statement must be true?

• No horizontal forces act once the crate has already started to slide across the floor

• Your applied push is less than friction because acceleration is zero during steady motion

• Your applied push equals the opposing kinetic friction in magnitude but in the opposite direction

• Your applied push is greater than friction, creating a nonzero net force that still yields constant speed

Which of the following is a non-contact force?

• Friction

• Tension

• Gravity

• Normal force

A student pushes a 5 kg box with a force of 40 N horizontally. If friction is 20 N, what is the net force?

• 0 N

• 2 N

• 20 N

• 60 N