Vibrations and Waves
Practice Test
1.
In Figure 14-14, how do the frequencies of the waves in pictures a and c compare?
a.
a's frequency is four times c's.
b.
a's frequency is half of c's.
c.
a's frequency is one-quarter of c's.
d.
a's frequency is twice c's.
Hint
2.
The formula
represents the period of a pendulum, T. What is the period of a 3.5 m-long pendulum on Earth?
a.
3.8 s
b.
3.2 s
c.
1.4 s
d.
4.6 s
Hint
3.
You lift a 2.73-kg textbook from the floor to a shelf 1.75 m above the floor. What is the book's gravitational potential energy relative to the floor?
a.
46.8 J
b.
14.3 J
c.
-46.8 J
d.
93.1 J
Hint
4.
The ratio of resistance force to effort force is called the __________.
a.
efficiency
b.
power
c.
torque
d.
mechanical advantage
Hint
5.
The first law of thermodynamics is a restatement of which law?
a.
second law of thermodynamics
b.
kinetic-molecular law
c.
gravity
d.
conservation of energy
Hint
6.
A forklift raises a box 2.5 m doing 8.7 kJ of work on it. What is the mass of the box?
a.
3.6×10
3
kg
b.
3.5×10
3
kg
c.
3.6×10
2
kg
d.
7.2×10
2
kg
Hint
7.
A 2.00-kg ball, A, is moving at a speed of 5.00 m/s. It collides with a stationary ball, B, of the same mass. After the collision, A moves off in a direction 30.0° to the left of its original direction. Ball B moves off in a direction 90.0° to the right of ball A's final direction. How fast is ball A moving after the collision?
a.
8.66 m/s
b.
2.50 m/s
c.
4.33 m/s
d.
6.83 m/s
Hint
8.
Objects that are lifted against the force of gravity have stored energy known as __________.
a.
kinetic energy
b.
reference levels
c.
resistance
d.
potential energy
Hint
9.
Waves become inverted if they reflect off a medium that is __________ than the initial medium.
a.
more gaseous
b.
less dense
c.
more dense
d.
softer
Hint
10.
In Figure 14-4, if you doubled the mass of the pendulum, what effect, if any, would it have on its period?
a.
The new period would be the old period, divided by the square root of two.
b.
The new period would be half the old period.
c.
It would have no effect.
d.
The new period would be the old period, times the square root of two.
Hint
11.
The rear wheel of a bicycle has a radius of 38.5 cm and has a gear with a radius of 4.75 cm. When the chain is pulled with a force of 175 N, the wheel rim moves 18.0 cm. The efficiency of this part of the bike is 95.0 percent. How far was the chain pulled to move the rim that amount?
a.
2.21 cm
b.
1.45×10
2
cm
c.
2.12 cm
d.
1.45 cm
Hint
12.
A hydrolic lift raises a 1.14×10
3
-kg car a distance of 2.4 m. If the car is lifted in 47 s, how much power does the lift produce?
a.
290 W
b.
570 kW
c.
58.2 W
d.
570 W
Hint
13.
Surface waves move in a position __________ to the direction of the wave motion.
a.
both parallel and perpendicular
b.
in a circular motion relative
c.
perpendicular
d.
parallel
Hint
14.
In Figure 11-13, case 3, if
v
i
were doubled, how would the magnitude of the final velocity be affected?
a.
It wouldn't change.
b.
It would be doubled.
c.
It would be halved.
d.
It would be quadrupled.
Hint
15.
A standing wave appears to be __________.
a.
fluctuating
b.
standing still
c.
moving very fast
d.
moving very slowly
Hint
16.
A 2.00-kg ball, A, is moving at a speed of 5.00 m/s. It collides with a stationary ball, B, of the same mass. After the collision, A moves off in a direction 30.0° to the left of its original direction. Ball B moves off in a direction 90.0° to the right of ball A's final direction. How fast is ball B moving after the collision?
a.
2.50 m/s
b.
8.66 m/s
c.
6.83 m/s
d.
5.00 m/s
Hint
17.
A collision in which kinetic energy decreases is called a(n) __________.
a.
mechanical collision
b.
elastic collision
c.
inelastic collision
d.
energy conservation
Hint
18.
Thermodynamics is the study of __________.
a.
heat
b.
light
c.
stars
d.
sound
Hint
19.
Absolute zero is __________.
a.
-273 K
b.
-273°C
c.
-273°F
d.
273 K
Hint
20.
Which is an example of a heat engine?
a.
solar panels
b.
volcano
c.
windmill
d.
automobile engine
Hint
