Question 1

A golf ball is dropped and experiences a gravitational force of $$0.450\ \mathrm{N}$$ downward and a drag force of $$0.050\ \mathrm{N}$$ upward. What is the net force acting on the golf ball?

Accepted Answer

$$0.400\ \mathrm{N}$$\ downward

Question 2

According to Newton's 1st Law, what happens to an object moving with constant velocity on a frictionless surface if no net force acts on it?

Accepted Answer

It will continue moving with constant velocity.

Question 3

A sled with a mass of $$30\ \mathrm{kg} is $$pulled with a horizontal force of $$70\ \mathrm{N} on $$snow, and the frictional force is $$10\ \mathrm{N}. $$What is the sled's acceleration?

Accepted Answer

$$2.7\ \mathrm{m/s^2$}$$

Question 4

A $$20\ \mathrm{kg}$$ sled is pulled with a force of $$50\ \mathrm{N} on $$gravel. If the sled moves at a constant velocity of $$1.2\ \mathrm{m/s}$$, what is the magnitude of the frictional force?

Accepted Answer

$$50\ \mathrm{N}$$

Question 5

A $$20\ \mathrm{kg}$$ sled is pulled with a force of $$50\ \mathrm{N} on $$gravel. If the sled's acceleration is $$0.20\ \mathrm{m/s^2$}$$, what is the magnitude of the frictional force?

Accepted Answer

$$46\ \mathrm{N}$$

Question 6

A skydiver with a mass of $$50\ \mathrm{kg}$$ experiences a drag force of $$100\ \mathrm{N}$$ upward. What is the acceleration of the skydiver? (Take $$g = 9.8\ \mathrm{m/s^2$}$$ downward.)

Accepted Answer

$$-7.8\ \mathrm{m/s^2$}$$

Question 7

Which of the following best describes Newton's 2nd Law?

Accepted Answer

The net force on an object is equal to its mass times its acceleration: $$F_{\mathrm{net}} = m a$$

Question 8

A professor with a mass of $$75\ \mathrm{kg}$$ jumps straight up, accelerating at $$1.0\ \mathrm{m/s^2$}. $$What force does the professor apply to the Earth?

Accepted Answer

$$810\ \mathrm{N}$$

Question 9

Which of the following is NOT a fundamental force of nature?

Accepted Answer

Frictional force

Question 10

In a tug-of-war, the blue team pulls with $$250\ \mathrm{N} to $$the left and the red team pulls with $$300\ \mathrm{N} to $$the right. What is the net force on the cart?

Accepted Answer

$$50\ \mathrm{N}$$\ to the right

Question 11

Which statement best describes Newton's 3rd Law?

Accepted Answer

For every force, there is an equal and opposite force acting on a different object.

Question 12

A car of mass $$1000\ \mathrm{kg}$$ accelerates at $$2.0\ \mathrm{m/s^2$}. $$What is the net force acting on the car?

Accepted Answer

$$2000\ \mathrm{N}$$

Question 13

Which of the following is a real-world example of Newton's 3rd Law?

Accepted Answer

A rocket launches upward as exhaust gases are expelled downward.

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.

Question 15

A $$5\ \mathrm{kg}$$ box is pushed with a force of $$30\ \mathrm{N} to $$the right. If the frictional force is $$10\ \mathrm{N} to $$the left, what is the acceleration of the box?

Accepted Answer

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

Newton’s Laws of Motion: Concepts, Applications, and Problem Solving

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