Phys 1000
Spring 2015
Name:_______________________________
Test 3
April 8, 2015
INSTRUCTIONS:
a) No books, notes, or other such materials are permitted.
b) NO CALCULATORS OR MOBILE PHONES ARE PERMITTED!!!
c) There is only one correct answer for each question. However, if you feel that more
than one answer is correct then you should choose the one you feel is most correct.
EACH QUESTION IS WORTH 5 POINTS
(There are 20 questions for a total of 100 points.)
g = 9.8 m/s/s = 32 ft/s/s
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1. You whirl a bucket of water in a big vertical circle. The water stays in the bucket at the top
of the circle because
(a) It experiences a centrifugal force pushing it against the bottom of the bucket.
(b) A sufficiently large inward force acts on it.
(c) Its speed is constant.
(d) Gravity stops acting on the water at the top of its motion.
2. You ride the loop-the-loop at the amusement park. At the moment you are upside down at
the top of the loop
(a) You are always weightless.
(b) You no longer feel the force of the track pushing against you.
(c) You could feel heavier than your normal weight if you are traveling very fast.
(d) You always need a safety belt to hold you in your seat.
3. You make a sharp left turn in your car. You feel as if you are being thrown outward because
(a) An object moving in a circle always has an outward force acting on it.
(b) The centrifugal force pulls you outward.
(c) You are accelerating outward.
(d) It is a reaction to the inward centripetal force.
4. On a warm day, the tires on your car
(a) Have a smaller volume.
(b) Have more air in them.
(c) Become less buoyant.
(d) Have higher pressure.
5. A sharp knife cuts a carrot better than a dull knife because
(a) There is less friction between the knife and the carrot.
(b) The force is greater when the blade is sharper.
(c) The cutting surface is larger.
(d) The pressure is greater for the same force.
6. When a helium-filled balloon is put into a surrounding environment of helium it
(a) Sinks.
(b) Rises more quickly than in air.
(c) Still rises but not as well as in air.
(d) Quickly collapses.
7. A hot-air balloon rises because
(a) There is a larger mass of air inside the balloon.
(b) The weight of the balloon plus the weight of the hot air inside is less than the weight of
the displaced cooler air.
(c) The volume of the balloon increases.
(d) The pressure inside the balloon is greater than outside the balloon.
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8. A steel ship floats in water because
(a) Hollow objects float.
(b) It is filled with air.
(c) It displaces an amount of water equal to its own weight.
(d) Its weight is small compared to the weight of the water it displaces.
9. A balloon filled with air is put into a container of liquid nitrogen (temperature = -1960 C =
-3210 F). The balloon becomes very small because
(a) Most of the air goes out from the balloon.
(b) The pressure inside the balloon decreases with decreasing temperature.
(c) The balloon material ruptures.
(d) Pressure decreases with decreasing volume.
10. A one-inch square column of air extending from the surface of the earth to the top of the
atmosphere weighs about
(a) 10 lbs.
(b) 15 lbs.
(c) 60 lbs.
(d) 200 lbs.
11. On the highway you meet an oncoming truck, and you feel as if you are drawn towards the
truck just as you pass by each other. This is because
(a) The slower moving air between your car and the truck has a higher pressure.
(b) The truck creates an increase in the air pressure between you and the truck.
(c) The truck creates a region of turbulent air in front of it.
(d) The faster moving air between your car and the truck has a lower pressure.
12. By increasing the size of the wake behind a water skier
(a) The water becomes less turbulent.
(b) The skier experiences a smaller drag force.
(c) The water flows more smoothly.
(d) The pressure drag is increased.
13. The Tacoma Narrows Bridge collapsed mainly because of
(a) Resonance.
(b) Large wind gusts.
(c) Too much traffic.
(d) Poor construction.
14. The loudness of the sound from a violin is determined by
(a) The amplitude of the oscillating string.
(b) The particular string that is set into vibration.
(c) Whether it is bowed or plucked.
(d) The frequency of the vibrating string.
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15. A singer who adjusts her voice to sing one octave higher
(a) Doubles the pitch of each note.
(b) Increases the bass notes.
(c) Sings louder.
(d) Makes the frequency of each note four times higher.
16. A plucked guitar string
(a) Always vibrates with a single frequency.
(b) Vibrates at lower pitch if the length of the string is made shorter.
(c) Becomes louder as the tension is increased.
(d) Can vibrate at its fundamental frequency and several of its harmonics at the same time.
17. In music, which of the following pair of frequencies represent a fifth?
(a) 220 and 440 Hz
(b) 220 and 330 Hz
(c) 440 and 880 Hz
(d) 220 and 660 Hz
18. For the music I played in class, less frequent oscillations on the screen represented
(a) Less volume.
(b) Lower pitch.
(c) Less amplitude.
(d) Higher frequency.
19. If you comb your hair and the comb becomes negatively charged
(a) Your hair gains an equal amount of negative charge.
(b) Electrons have been transferred from the comb to your hair.
(c) Your hair gains an equal amount of positive charge.
(d) Your hair and the comb will repel each other.
20. In a semiconducting material
(a) Electrons cannot move.
(b) Protons are free to move.
(c) Charges can move if light is shined on the material.
(d) Charges are always free to move.
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