Q: A ball is dropped from rest from a height of 20 m. Neglecting air resistance, what is the velocity of the ball just before it hits the ground? (Take $$g = 9.8\ \mathrm{m/s^2$})$$

$$v = \sqrt{2gh} = \sqrt{2 \times 9.8 \times 20} = 19.8\ \mathrm{m/s}$$

Q: A car starts from rest and accelerates at $$3\ \mathrm{m/s^2$}$$ for $$8\ \mathrm{s}. $$What is its final velocity?

$$v = v_0$ + at = 0 + 3 \times 8 = 24\ \mathrm{m/s}$$

Question 1

A car moves along a straight road such that its position-versus-time graph is a straight line with a positive slope. Which of the following statements is true about the car's motion?

Accepted Answer

The car is moving at a constant velocity to the right.

Question 2

The area under a velocity-versus-time graph for an object represents which physical quantity?

Accepted Answer

The object's displacement.

Question 3

A ball is dropped from rest from a height of 20 m. Neglecting air resistance, what is the velocity of the ball just before it hits the ground? (Take $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$v = \sqrt{2gh} = \sqrt{2 	imes 9.8 	imes 20} = 19.8\ \mathrm{m/s}$$

Question 4

Which of the following best describes the acceleration of an object in free fall near the surface of the Earth (neglecting air resistance)?

Accepted Answer

It is constant and directed downward.

Question 5

A train travels 30 km in 15 minutes at a constant speed. How long will it take to travel 90 km at the same speed?

Accepted Answer

45 minutes

Question 6

A car accelerates uniformly from rest to a velocity of $$20\ \mathrm{m/s} in$$ $$5\ \mathrm{s}. $$What is the car's acceleration?

Accepted Answer

$$a = \frac{\Delta v}{\Delta t} = \frac{20}{5} = 4\ \mathrm{m/s^2$}$$

Question 7

A cyclist riding at $$10\ \mathrm{m/s}$$ sees a stop sign and comes to a complete stop in $$4\ \mathrm{s}. $$What is the magnitude of the cyclist's acceleration?

Accepted Answer

$$a = \frac{0 - 10}{4} = -2.5\ \mathrm{m/s^2$}$$

Question 8

Which of the following statements about uniform motion is correct?

Accepted Answer

The position-versus-time graph is a straight line.

Question 9

A rock is thrown straight up with an initial velocity of $$15\ \mathrm{m/s}. $$How long does it take to reach its highest point? (Take $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$t = \frac{v_0$}{g} = \frac{15}{9.8} = 1.53\ \mathrm{s}$$

Question 10

A velocity-versus-time graph for an object is a straight line with a negative slope. What does this indicate about the object's motion?

Accepted Answer

The object is moving with constant negative acceleration.

Question 11

A 1-kg ball and a 10-kg ball are dropped from the same height in a vacuum. Which statement is correct?

Accepted Answer

Both balls hit the ground at the same time.

Question 12

A car starts from rest and accelerates at $$3\ \mathrm{m/s^2$}$$ for $$8\ \mathrm{s}. $$What is its final velocity?

Accepted Answer

$$v = v_0$ + at = 0 + 3 	imes 8 = 24\ \mathrm{m/s}$$

Question 13

A position-versus-time graph is a parabola opening upwards. What does this indicate about the object's motion?

Accepted Answer

The object is accelerating with constant positive acceleration.

Question 14

A Boeing 747 accelerates at $$2.6\ \mathrm{m/s^2$}$$ from rest to a takeoff speed of $$70\ \mathrm{m/s}. $$What is the minimum runway length required for takeoff?

Accepted Answer

$$x = \frac{v^2$}{2a} = \frac{70^2$}{2 	imes 2.6} = 942\ \mathrm{m}$$

Question 15

Which of the following is a correct statement about the instantaneous velocity of an object?

Accepted Answer

It is the slope of the position-versus-time graph at a specific instant.

Question 16

A car moving to the right slows down. What is the sign of its acceleration?

Accepted Answer

Negative

Question 17

A ball is thrown straight up. At the very top of its path, what is its acceleration?

Accepted Answer

$$-g$$

Question 18

A drag racer starts from rest and travels 6.0 m in 1.0 s with constant acceleration. How far will it travel in 5.0 s?

Accepted Answer

$$6.0 	imes (5.0/1.0)^2$ = 150\ \mathrm{m}$$

Motion in One Dimension: Structured Study Notes

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드