Question 1

Which of the following best describes Newton's First Law of Motion (the law of inertia)?

Accepted Answer

An object at rest will remain at rest, and an object in motion will continue in motion at constant speed in a straight line unless acted upon by a nonzero net force.

Question 2

A 10-kg box is pulled to the right with a force of 30 N and to the left with a force of 20 N. What is the net force acting on the box?

Accepted Answer

$$10\ \mathrm{N} to $$the right

Question 3

A car travels 150 km in 3 hours. What is its average speed?

Accepted Answer

$$50\ \mathrm{km/h}$$

Question 4

Which of the following is a vector quantity?

Accepted Answer

Velocity

Question 5

A ball is dropped from rest and falls freely under gravity. What is its speed after 3 seconds? (Assume $$g = 10\ \mathrm{m/s^2$})$$

Accepted Answer

$$30\ \mathrm{m/s}$$

Question 6

A skydiver reaches terminal velocity when:

Accepted Answer

The upward force of air resistance equals the downward force of gravity.

Question 7

If you push a crate at a steady speed in a straight line and the friction force is $$75\ \mathrm{N}$$, how much force must you apply?

Accepted Answer

$$75\ \mathrm{N}$$

Question 8

A 5-kg iron ball and a 10-kg iron ball are dropped from rest in a vacuum. When the 5-kg ball reaches a speed of $$10\ \mathrm{m/s}$$, what is the speed of the 10-kg ball?

Accepted Answer

$$10\ \mathrm{m/s}$$

Question 9

A soccer player kicks a ball with $$1500\ \mathrm{N} of $$force. According to Newton's Third Law, the ball exerts a force on the player's foot of:

Accepted Answer

$$1500\ \mathrm{N}$$

Question 10

A 20-N falling object encounters $$5\ \mathrm{N} of $$air resistance. What is its acceleration? (Assume $$g = 10\ \mathrm{m/s^2$}$$ and mass $$= 2\ \mathrm{kg})$$

Accepted Answer

$$7.5\ \mathrm{m/s^2$}$$

Question 11

A person stands with one foot on each of two bathroom scales, distributing their weight evenly. If the person weighs $$800\ \mathrm{N}$$, what does each scale read?

Accepted Answer

$$400\ \mathrm{N}$$

Question 12

A car rounds a curve at a steady speed. Is it accelerating?

Accepted Answer

Yes, because its direction is changing.

Question 13

A 2-kg object is acted on by a net force of $$8\ \mathrm{N}. $$What is its acceleration?

Accepted Answer

$$4\ \mathrm{m/s^2$}$$

Question 14

A plane is flying north at $$80\ \mathrm{km/h}$$ and encounters a crosswind blowing east at $$60\ \mathrm{km/h}. $$What is the plane's resultant speed?

Accepted Answer

$$100\ \mathrm{km/h}$$

Question 15

Which of the following statements about action and reaction forces is correct?

Accepted Answer

They always act on different objects.

Question 16

A bird flies by pushing air downward with its wings. According to Newton's Third Law, what happens?

Accepted Answer

The air pushes the bird upward with an equal force.

Question 17

A block is at rest on a table. Which forces are acting on it?

Accepted Answer

Gravity downward and support force upward

Question 18

A 1-kg object weighs approximately how many newtons on Earth's surface?

Accepted Answer

$$9.8\ \mathrm{N}$$

Question 19

If you toss a coin straight up while riding in a train moving at constant velocity, where will the coin land?

Accepted Answer

Back in your hand

Newton's Laws of Motion and Linear Motion: Study Notes for Physics with Calculus

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