Question 1

Which of the following best describes a free-body diagram?

Accepted Answer

A diagram representing all the forces acting on an object, with the object shown as a point and forces as arrows.

Question 2

A box is being pushed to the right across a rough floor. Which forces should be included in its free-body diagram?

Accepted Answer

The force of the push, friction, normal force, and gravity.

Question 3

A man pulls a block with a rope at an angle above the horizontal. Which of the following is NOT a force acting on the block?

Accepted Answer

Force exerted by the man’s feet.

Question 4

If an object is at rest and remains at rest, what can you conclude about the net force acting on it?

Accepted Answer

The net force is zero.

Question 5

A crate of mass $$m is $$being pushed across a rough floor with a constant velocity. What is the magnitude of the net force acting on the crate?

Accepted Answer

$$F_{net} = 0$$

Question 6

A rock is thrown directly upward. Immediately after it leaves your hand, which forces act on it?

Accepted Answer

Gravity and air resistance.

Question 7

Which statement about the arrows in a free-body diagram is correct?

Accepted Answer

The arrows start at the object and their length represents the magnitude of the force.

Question 8

A heavy block is at rest on a level floor. Which of the following is the correct pair of forces acting on the block?

Accepted Answer

Normal force upward and weight downward.

Question 9

A car is parked on a hill. Which of the following must be true for the car to remain at rest?

Accepted Answer

The net force on the car is zero.

Question 10

A block of mass $$m is $$suspended by a rope and is at rest. What is the tension $$T in $$the rope?

Accepted Answer

$$T = m g$$

Question 11

An elevator is moving upward at constant speed. Which statement about the forces acting on the elevator is correct?

Accepted Answer

The upward tension force equals the downward weight.

Question 12

A block slides down a frictionless incline. Which forces act on the block?

Accepted Answer

Gravity and normal force.

Question 13

A person pulls a block with a rope at an angle $$	heta$$ above the horizontal. If the tension in the rope is $$T$$, what is the vertical component of the tension?

Accepted Answer

$$T \sin 	heta$$

Question 14

Which of the following is a non-contact force that should be included in a free-body diagram?

Accepted Answer

Gravitational force.

Question 15

A block of mass $$m is $$accelerating down an incline with negligible friction. What is the net force acting on the block?

Accepted Answer

$$F_{net} = m g \sin 	heta$$

Question 16

Which of the following is the correct expression for the gravitational force acting on an object of mass $$m$$ near Earth's surface?

Accepted Answer

$$F_g = m g$$

Question 17

A box is being pulled to the right with a force $$F_{pull}$$ while friction $$F_{friction}$$ acts to the left. If the box accelerates to the right, which equation correctly represents the net force?

Accepted Answer

$$F_{net} = F_{pull} - F_{friction}$$

Question 18

A block is at rest on a table. If the weight of the block is $$w$$, what is the magnitude of the normal force exerted by the table?

Accepted Answer

$$F_{normal} = w$$

Question 19

Which of the following is NOT a correct step in drawing a free-body diagram?

Accepted Answer

Include forces that the object exerts on other objects.

Question 20

A block of mass $$m is $$pulled by a rope with tension $$T at an $$angle $$	heta$$ above the horizontal. If the block moves at constant velocity, what is the relationship between the horizontal component of tension and friction force $$f$$?

Accepted Answer

$$T \cos 	heta = f$$

Free-Body Diagrams and Net Forces: Study Notes for Physics

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