Q: A block is pulled by a rope with a force $$F at an $$angle $$\theta$$ above the horizontal. What are the $$x$$ and $$y$$ components of the force?

$$F_x = F \cos \theta$$, $$F_y = F \sin \theta$$

Q: A 0.45 kg bottle is shoved at an initial speed of 2.8 m/s and stops after moving 1 m. What is the acceleration of the bottle?

$$a = \frac{(0^2$ - 2.8^2$)}{2 \times 1}$$

Question 1

A 150-kg football player collides head-on with a 75-kg running back. During the collision, the heavier player exerts a force $$F_A on $$the smaller player. According to Newton's Third Law, what is the magnitude of the force $$F_B$$ that the smaller player exerts back on the heavier player?

Accepted Answer

$$F_B = F_A$$

Question 2

Which of the following best describes the normal force acting on a book resting on a table?

Accepted Answer

A force exerted by the table upward, perpendicular to its surface

Question 3

A block is pulled by a rope at an angle of $$30^	ext{o}$$ above the horizontal with a force of 10 N. What is the vertical component of the force?

Accepted Answer

$$10 	imes \sin 30^	ext{o}$$

Question 4

Which of the following is NOT a contact force?

Accepted Answer

Weight (gravitational force)

Question 5

A puck moves with constant velocity on an air hockey table. What is the net force acting on the puck?

Accepted Answer

The net force is zero

Question 6

A spring scale measures a downward force $$F_1 of 1.00 cm $$and a horizontal force $$F_2 of 2.00 cm. $$What is the total elongation of the spring when both forces are applied simultaneously at right angles?

Accepted Answer

$$\sqrt{(1.00)^2$ + (2.00)^2$} = 2.24 cm$$

Question 7

A person pulls a block across the floor with a rope. Which force is the action-reaction pair according to Newton's Third Law?

Accepted Answer

The force of the rope on the block and the force of the block on the rope

Question 8

A 10-N push is directed $$45^	ext{o}$$ below the horizontal. What is the horizontal component of the force?

Accepted Answer

$$10 	imes \cos 45^	ext{o}$$

Question 9

Which statement is most correct regarding motion and forces?

Accepted Answer

Both statements are correct.

Question 10

A car is traveling at constant velocity on a straight road. Which statement about the net force on the car is correct?

Accepted Answer

The net force is zero

Question 11

A block is pulled by a rope with a force $$F at an $$angle $$	heta$$ above the horizontal. What are the $$x$$ and $$y$$ components of the force?

Accepted Answer

$$F_x = F \cos 	heta$$, $$F_y = F \sin 	heta$$

Question 12

A person is standing at rest and begins to walk forward. What force pushes the person forward?

Accepted Answer

The force of the ground on the person's feet

Question 13

A block is placed on an inclined plane. Which component of the block's weight causes it to slide down the plane?

Accepted Answer

$$mg \sin 	heta$$

Question 14

Which of the following best describes an inertial frame of reference?

Accepted Answer

A frame in which Newton's first law is valid

Question 15

A block is acted upon by two forces $$\vec{F}_1$$ and $$\vec{F}_2 at a $$point $$O. $$What is the resultant force $$\vec{R}$$?

Accepted Answer

$$\vec{R} = \vec{F}_1 + \vec{F}_2$$

Question 16

A 0.45 kg bottle is shoved at an initial speed of 2.8 m/s and stops after moving 1 m. What is the acceleration of the bottle?

Accepted Answer

$$a = \frac{(0^2$ - 2.8^2$)}{2 	imes 1}$$

Question 17

Which of the following is a real-life example of Newton's First Law?

Accepted Answer

A hockey puck gliding on an air hockey table at constant velocity

Question 18

If a block is at rest on a table, which forces act on it?

Accepted Answer

Both the weight and the normal force

Question 19

A block is pulled horizontally with a constant force. If the block moves at constant velocity, what can be said about the net force?

Accepted Answer

The net force is zero

Newton’s Laws of Motion: Forces and Their Applications

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