Question 1

Which of the following best describes a force?

Accepted Answer

A vector quantity that has both magnitude and direction.

Question 2

A 2 kg object is acted on by a net force of $$\6$$\;\mathrm{N}\$ to the right. What is its acceleration?

Accepted Answer

$$\3$$\;\mathrm{$$m/s^2$$}\$ to the right

Question 3

Which of the following is an example of a long-range force?

Accepted Answer

Gravitational attraction between Earth and a satellite

Question 4

A book rests on a table. Which force is responsible for supporting the book against gravity?

Accepted Answer

Normal force

Question 5

A skier is being towed up a hill at constant speed. Which statement is true about the net force acting on the skier?

Accepted Answer

The net force is zero.

Question 6

A car is parked on a hill. Which forces must be included in its free-body diagram?

Accepted Answer

Weight, normal force, and static friction

Question 7

A rocket launches vertically. Which force propels the rocket upward?

Accepted Answer

Thrust force

Question 8

A box is pulled by two ropes at right angles, with $$\$$\vec{F}_1 = 10\;\mathrm{N}\$$ north and $$\$$\vec{F}_2 = 10\;\mathrm{N}\$$ east. What is the magnitude of the net force?

Accepted Answer

$$\14.1$$\;\mathrm{N}\$

Question 9

A 5 kg sled is pulled with a force of $$\20$$\;\mathrm{N}\$$ to the right. If the friction force is $$\$$5\;\mathrm{N}\ to $$the left, what is the acceleration?

Accepted Answer

$$\4$$\;\mathrm{$$m/s^2$$}\$ to the right

Question 10

Which of the following best illustrates Newton’s Third Law?

Accepted Answer

A hammer hits a nail, and the nail pushes back on the hammer.

Question 11

A mosquito collides head-on with a truck. According to Newton’s Third Law, during the collision:

Accepted Answer

Both exert equal and opposite forces on each other.

Question 12

A crate is at rest on a horizontal surface. Which force prevents it from moving when a small horizontal force is applied?

Accepted Answer

Static friction

Question 13

A basketball is released from rest in a stiff breeze directed to the right. In what direction does the ball accelerate?

Accepted Answer

Downward and to the right

Question 14

If the net force on an object is zero, which of the following must be true?

Accepted Answer

The object moves with constant velocity or is at rest.

Question 15

A 10 kg box is pulled across a floor with a constant velocity by a horizontal force of $$\30$$\;\mathrm{N}\$. What is the friction force acting on the box?

Accepted Answer

$$\30$$\;\mathrm{N}\$

Question 16

A compressed spring exerts a force on a box. What type of force is this?

Accepted Answer

Spring force

Question 17

A car is stuck in the mud. You tie a rope to the car and a tree, then pull sideways on the middle of the rope. Why does this technique allow you to apply a larger force to the car than you could directly?

Accepted Answer

The vector sum of the forces at the center increases the force on the car.

Question 18

Which of the following is true about the direction of the normal force?

Accepted Answer

It is always perpendicular to the surface.

Question 19

If the mass of an object is doubled while the net force remains constant, what happens to the acceleration?

Accepted Answer

It is halved.

Question 20

A person pushes backward on the ground while walking. According to Newton’s Third Law, what is the reaction force?

Accepted Answer

The ground pushes forward on the person.

Chapter 4: Forces and Newton’s Laws of Motion – Structured Study Notes

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