Reading QuizReview

A ball rolls off the table and hits the floor. Which of the following statements is TRUE?

• A ball rolling on the table with a faster speed will hit the floor in the same amount of time

• A ball rolling on the table with a faster speed will spend less time in the air before hitting the floor.

• A ball rolling on the table with a faster speed will spend more time in the air before hitting the floor

Fig. 3.14

vx = v0x + axt

x = x0 + v0x + (1/2)axt2

vy = v0y + ayt

y = y0 + v0yt + (1/2)ayt2

vx = v0x

x = v0xt

vy = ayt

y = (1/2)ayt2

Uniform acceleration means a = constant. This leads to two “simple” equations:

€

v=v0 +at

€

d = d0 + v0t + 12 at 2

Uniform acceleration means a = constant. This leads to two “simple” equations:

€

v=v0 +at

€

d=v0t+12at

2

Question 1

Choose the correct statement:

A. Ignoring air resistance, heavier objects fall faster than light objects.

B. All objects fall through air with the same acceleration.

C. An object thrown to the ground accelerates faster than an object that is merely dropped.

D. The rate of change of velocity of a falling object increases with time.

E. None of the above.

Question 2: You are riding on a Ferris wheel at an amusement park, making one revolution every 30 seconds. Choose the TRUE statement:

A. Your acceleration is greatest at the top.

B. Your acceleration is greatest at the bottom.

C. The size of your acceleration never changes.

D. The direction of your acceleration never changes.

E. You have no acceleration.

Summary of Ch 2, continued:

4. Motion can be graphed. The slope of distance vs. time is instantaneous speed. The slope of velocity vs. time is acceleration.

5. Uniform acceleration means a = constant. This leads to two “simple” equations:

€

v=v0 +at

€

d = d0 + v0t + 12 at 2

LECTURE QUIZ - Question 3

I drop a basketball from rest. Assume that a=10m/s2. How far does it fall in half a second? (Choose closest answer.)

A. 0.500 m

B. 1.000 m

C. 1.125 m

D. 2.500 m

E. 5.000 m

LECTURE QUIZ - Question 4

A bullet is shot horizontally with a speed of 200 m/s. The target is 100 meters away. How far does the bullet fall before hitting the target?

A. Zero - it doesn’t fall.

B. about one millimeter

C. about one centimeter

D. about 10 centimeters

E. more than one meter

Figure 3.10The velocity vectors at different points in the flight of a ball

thrown upward with a starting velocity of +20 m/s.

Figure 3.11A plot of the velocity versus time for a ball thrown upward with an initial velocity of +20 m/s. The negative values of

velocity represent downward motion.