Yellow Exam

Multiple Choice and True/False Questions: 15 pts total

1-2.  (True/False) A speaker is producing a sound wave with a frequency of 200 Hz.

1.  True (a) or False (b)           It takes a longer time for this sound wave to travel from the speaker to my ear than would a sound wave of 400 Hz.

2.  True (a) or False (b)           If I operated this speaker on the surface of the moon, it would sound the same.

3.  If a violin string is tuned such that the fundamental frequency is 440 Hz, the frequency of the tone from the violin string oscillating in the third harmonic mode is

a. same as the fundamental frequency         

b. higher than the fundamental frequency         

c. lower than the fundamental frequency         

4. A water tank, hose, and valve are shown below with points A and B as marked.

The pressure at the faucet (point B) is:
a. the same as the pressure at point A
b. greater than the pressure at point A
c. less than the pressure at point A
d. it could be either greater than or less than the pressure at point A, there is no way to tell. 

 

5. You are putting all of your textbooks on the top shelf of your bookshelf.  The books start out on the ground and the shelf is 2 m up.  You have 10 books, each with a mass of 2 kg.  How much work does it take to put the books on the shelf? (Choose the answer that is closest to the correct value.)

a. 200 J;      b. 200 N;      c. 40 J;       d. 400 J;       e.  20 N

6. A tone is heard when plucking the thickest string on a violin.  Compared to that tone, the frequency of the tone heard when plucking the thinnest string on the violin
a. is higher because there is more tension in the string
b. is lower because there is less tension in the string.
c. is higher because of the string’s smaller mass
d. is lower because of the string’s smaller mass

e. is different only because a different type of material is used.

7. Two skiers are racing down a very slick hill to the finish line (no friction), with the larger skier (130 kg) crossing the line 0.1 seconds ahead of the smaller one (73 kg) and 10 m to the right of where the smaller one crossed.  After the finish line the hill slopes upward to bring them to a stop, but it slopes upward at a 10% grade in front of the heavy skier and at a 25% grade in front of the light skier.  (A 10% grade means you gain 1 meter in height for every 10 meters in distance). 
Smaller Skier:
Larger Skier: 

Both skiers are going 23 m/s when they cross the line.  Both skiers continue straight up the hill without braking until they come to a stop.  When they have both stopped

a. the heavy skier is higher above the finish line;          
b. they are at the same height above the finish line;           
c. the lighter skier is higher above the finish line;                 
d. you cannot tell from the information given.  

8 - 10. The water pipe coming into the ground floor of an office building in downtown Denver has a water pressure of 300,000 Pa.

8. What is the highest level to which the water will rise up in the pipes in the building?

a. 15 m;       b. 31 m;       c. 61 m;      d. 150 m;      e. 310 m

9. On the 3^nd floor of the office building, what is (are) the principle form(s) of energy for the water in the large main water pipe through the building?
a. gravitational potential energy  b. pressure potential energy       c. kinetic energy           
d. a and b        e. b and c

10. If you opened a faucet on the ground floor of the building, how fast would the water come out?

a. 12.2 m/s;      b. 17.3 m/s;     c. 300 m/s;     d. 24.5 m/s;     e. 600 m/s

11. You are building a water system for your house where you pump water out of a well up into a water tower in the back yard.  If you want to make sure that the water pressure at the kitchen sink never drops below 250 kPa no matter how much water is in the water tower, how high above the sink must the bottom of the water tower be?  (Choose the answer closest to the correct value.)

a. 15 m;     b. 20 m;      c. 25 m;     d. 30 m;     e. 35 m

12. A sound wave with a frequency of 300 Hz strikes your ear.  At one instant in time there is a maximum of the pressure pushing on your eardrum.  How far away from your ear is the next high pressure region of the sound wave at that instant?

a. 1.1 m                       b. 0.9 cm                      c. 0.9 m            d. 11 m

e. impossible to know without more information.

13. A weight oscillating up and down on a spring has the most kinetic energy when it is

a. at the top;       b. in the middle;      c. at the bottom;     d. some other position

14-15. When a car skids on dry pavement the frictional force on the car is just about 0.7 times the weight of the car.  Experiments have shown that this does not depend very much on the kind of car or the tires. 

14.  A car is speeding down Hwy 36.  The driver slams on his brakes and starts skidding when he sees a deer jump into the road.  While the car is skidding,
a. the car’s kinetic energy is decreasing, but the gravitational potential energy of the car is increasing.
b. the car’s kinetic energy is unchanged because energy is always conserved.

c. the car’s kinetic energy is increasing because the skidding process adds energy to the system.

d. the car’s kinetic energy is decreasing, but the temperature of the car’s tires and the road is increasing.
e. the car’s kinetic energy is decreasing; this energy has been completely used up.

15. A 1200 kg Honda left a skid mark of 73 meters. How fast was the car going when it slammed on its brakes?

a. 600,900 m/s   b. 1002 m/s    c.  10.1 m/s      d. 22.4 m/s       e. 31.6 m/s