Q: A 10-N force is applied at an angle of $$30^\\circ$$ above the horizontal. What is the vertical component of the force?

$$10 \\sin 30^\\circ = 5 \\text{ N}$$

Q: Which of the following is the correct SI unit for force?

$$1 \\text{ N} = 1 \\text{ kg} \\cdot \\text{m}/\\text{s}^2$$

Q: A $$10 \\text{ N}$$ force is applied at $$45^\\circ$$ below the horizontal. What is the horizontal component of the force?

$$10 \\cos 45^\\circ = 7.07 \\text{ N}$$

Question 1

Which of the following statements best describes Newton's First Law of Motion?

Accepted Answer

An object acted on by zero net force moves with constant velocity and zero acceleration.

Question 2

A 10-N force is applied at an angle of $$30^\circ$$ above the horizontal. What is the vertical component of the force?

Accepted Answer

$$10 \sin 30^\circ = 5 \text{ N}$$

Question 3

Which of the following is NOT a contact force?

Accepted Answer

Weight

Question 4

A block of mass $$2 \text{ kg} is at $$rest on a frictionless surface. A force of $$6 \text{ N} is $$applied horizontally. What is the acceleration of the block?

Accepted Answer

$$3 \text{ m/s}^2$$

Question 5

Which equation correctly relates mass and weight on Earth?

Accepted Answer

$$W = m g$$

Question 6

A 250-kg linebacker exerts a force on the ground while running. According to Newton's Third Law, what is true about the force the ground exerts on the linebacker?

Accepted Answer

It is equal in magnitude and opposite in direction to the force exerted by the linebacker.

Question 7

A puck moves at constant speed in a circle of radius $$r on a $$frictionless table, tied to a string. What is the direction of the net force acting on the puck?

Accepted Answer

Toward the center of the circle

Question 8

Which of the following is the correct SI unit for force?

Accepted Answer

$$1 \text{ N} = 1 \text{ kg} \cdot \text{m}/\text{s}^2$$

Question 9

A $$0.45 \text{ kg}$$ bottle slides across a table and comes to rest after $$1.0 \text{ m}. If $$its initial velocity is $$2.8 \text{ m/s}$$, what is the magnitude of the net force acting on the bottle (assume constant friction)?

Accepted Answer

$$-1.8 \text{ N}$$

Question 10

Which statement about free-body diagrams is correct?

Accepted Answer

They show all the forces acting on the chosen object, including magnitude and direction.

Question 11

A $$4.0 \text{ kg}$$ block and a $$5.0 \text{ kg}$$ block are connected by a rope and pulled upward with a force of $$200 \text{ N}. $$What is the acceleration of the system? (Assume $$g = 9.8 \text{ m/s}^2)$$

Accepted Answer

$$2.2 \text{ m/s}^2$$

Question 12

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 13

A $$1 \text{ kg}$$ object weighs $$1.62 \text{ N} on $$the surface of the moon. What is the acceleration due to gravity on the moon?

Accepted Answer

$$1.62 \text{ m/s}^2$$

Question 14

Which of the following best describes the superposition principle for forces?

Accepted Answer

The net force is the vector sum of all individual forces acting on an object.

Question 15

A $$10 \text{ N}$$ force is applied at $$45^\circ$$ below the horizontal. What is the horizontal component of the force?

Accepted Answer

$$10 \cos 45^\circ = 7.07 \text{ N}$$

Question 16

Which of the following is a correct statement of Newton's Second Law?

Accepted Answer

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

Question 17

A $$1 \text{ kg}$$ object is dropped from rest near the surface of the Earth. What is the magnitude of the gravitational force acting on it?

Accepted Answer

$$9.8 \text{ N}$$

Question 18

Which of the following is true about action-reaction pairs according to Newton's Third Law?

Accepted Answer

They have equal magnitude and opposite direction.

Question 19

A $$5 \text{ kg}$$ object is acted upon by two forces: $$8 \text{ N} to $$the right and $$3 \text{ N} to $$the left. What is the acceleration of the object?

Accepted Answer

$$1 \text{ m/s}^2 to $$the right

Newton's Laws of Motion: Study Notes and Applications

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