Question 1

A box is being pushed to the right across a rough horizontal surface with an applied force of 35 N. The frictional force opposing the motion is 5 N, the weight of the box is 30 N downward, and the buoyancy force from the air is 30 N upward. What is the magnitude and direction of the resultant force acting on the box?

Accepted Answer

Question 2

In a free-body diagram, which of the following statements is TRUE regarding the representation of forces?

Accepted Answer

Each force is represented as a vector arrow, with the length indicating magnitude and the direction indicating the force's direction.

Question 3

A book rests on a table. The weight of the book is 10 N downward, and the normal reaction force from the table is 10 N upward. What is the resultant force acting on the book?

Accepted Answer

0 N

Question 4

Two people are playing tug-of-war. Person A pulls with a force of 30 N to the left, and Person B pulls with a force of 40 N to the right. What is the resultant force and its direction?

Accepted Answer

10 N to the right

Question 5

A box is acted upon by three forces: 7 N to the left, 25 N to the right, and 10 N downward. What is the magnitude of the resultant force?

Accepted Answer

$$\sqrt{18^2$ + 10^2$} = \sqrt{324 + 100} = \sqrt{424} \approx 20.6 N$$

Question 6

According to Newton's First Law, what will happen to an object moving at constant velocity if the resultant force acting on it becomes nonzero?

Accepted Answer

Its motion will change; it may speed up, slow down, or change direction.

Question 7

A car is moving at constant velocity. The driving force is 6 N forward, and the only other force acting is friction. What is the value and direction of the frictional force?

Accepted Answer

6 N backward

Question 8

Which of the following is NOT a correct rule for drawing a free-body diagram?

Accepted Answer

Forces should be drawn with equal length arrows regardless of magnitude.

Question 9

A box is pushed up a slope. Which force acts perpendicular to the slope?

Accepted Answer

Normal contact force

Question 10

If the resultant force acting on a football is zero, which of the following statements is TRUE?

Accepted Answer

The football could be moving at constant velocity.

Question 11

A box is acted upon by a 30 N force upward and a 10 N force downward. What is the net force and its direction?

Accepted Answer

20 N upward

Question 12

In a free-body diagram, which force is always directed away from the mass?

Accepted Answer

Tension

Question 13

A box is acted upon by two forces: 10 N to the right and 10 N to the left. What is the resultant force?

Accepted Answer

0 N

Question 14

Which of the following best describes balanced forces?

Accepted Answer

Forces that cancel each other out, resulting in zero net force.

Question 15

A box is acted upon by a 14 N force to the left and an 8 N force to the right. What is the resultant force and its direction?

Accepted Answer

6 N to the left

Question 16

Which of the following is a correct step when calculating the resultant force in two dimensions?

Accepted Answer

Use Pythagoras' theorem to combine perpendicular force components.

Question 17

A box is acted upon by a 30 N force upward and a 10 N force downward. What is the resultant force?

Accepted Answer

20 N upward

Question 18

Which force acts in the opposite direction to the motion of a mass sliding down a slope?

Accepted Answer

Frictional force

Question 19

A box is acted upon by a 25 N force to the right and a 7 N force to the left. What is the resultant horizontal force?

Accepted Answer

18 N to the right

Question 20

Which of the following is NOT a common force to apply in a free-body diagram?

Accepted Answer

Magnetic force (in most everyday scenarios)

Forces and Free-Body Diagrams: Foundations of Newtonian Mechanics

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