Physics 103 Final (In Class Quiz Questions)

You hear a fire truck with a certain intensity, and you are about 1 mile away. Another person hears the same fire truck with an intensity that is about 10 times less. Roughly, how far is the other person from the fire truck? A) About the same distance B) About 3 miles C) About 10 miles D) About 30 miles E) About 100 miles Explain.

B) About 3 miles Intensity drops with the inverse quare of the distance, so if intensity drops by a factor of 10, the other person must be squared10 farther away, so about 3.

A blood platelet drifts along with the flow of blood through an artery that is partially blocked. As the platelet moves from the wide region into the narrow region, the blood pressure: A) Increases B) Decrease C) Stays the same D) Drops to zero Explain.

B) Decreases Speed increases in teh narrow part, according to continuity equation. Becuase the speed is higher, the pressure is lower, from Bernouli's principle.

A string is clamped at both ends and then plucked so that it vibrates in a standing mode between two extreme positions a and b. Let upward motion correspond to positive velocities. When the string is in position b, the instantaneous velocity of points along the string: A) Is zero everywhere B) Is positive everywhere C) Is negative everywhere D) Depends on the location along the string explain

A) Is zero everywhere both points change direction before and after B so at B all points must have zero velocity

How is smoke drawn up a chimney affected when there is a wind blowing outside? A) Smoke rises more rapidly in the chimney B) Smoke is unaffected by the wind blowing C) Smoke rises more slowly in the chimney D) Smoke is forced back down the chimney Explain.

A) Smoke rises more rapidly in the chimney due to the sped of the wind at the top of the chimney, there is a relativley lower pressure up there as compared to the bottom. Smoke is actually drawn up the chimney more rapidly, due to this pressure diff.

You are heading toward an island in a speedboat and you see your friend standing on the shore, at the base of a cliff. You sound the boat's horn to alert your friend of your arrival. If the horn has a rest frequency of f0, what frequency does your friend hear ? a) lower than F0 b) equal to F0 c) higher than F0 Question 1 Explain.

C) Higher than F0 Due to the approach of the source toward the stationary observer, the frequency is shifted higher

An empyt plastic soda bottle has been sitting out in the sunsine on a warm day. You put the cap on tightly and place the bottle in a refrigerator. What happens to the bottle as it cools? A) It expands and may burst B) It does not change C) It contracts and the sides collapse inward D) It is too dark in the fridge to tell explain.

C) It contracts and the sides collapse inward. initially the air inside the bottle is warm. it cools when placed in the fridge. as the temperature drops, the pressure drops. it will become lower than pressure outside (atmospheric) and being to collapse the bottle.

You put a straw into a glass of water, place your finger over the top so no air can get in or out, and then lift the straw from the liquid. You find that the straw retains some liquid. How does the air pressure P in the upper part compare to atmospheric pressure PA? a) greater than PA b) equal to PA c) less than PA Explain.

C) Less than Pa Forces acting at the bottom of the straw (Pa-P-PGH=0), so net force is zero. P=Pa-PGH we see that the pressure P inside the straw must be less than the outside pressure PA

2 cylinders at the same temperature contain the same gas. if B has twice the volume and half the number of moles as A, how does the pressure in B compare with the pressure in A? A) Pb=1/2Pa B) Pb=2Pa C) Pb=1/4Pa D) Pb= 4Pa E) Pb=Pa explain.

C) Pb=1/4 Pa Pv=NRT B has a factor of twice the volume, it has a factor of 2 less the pressure. B has half the amount of gas, so it is a factor of 2 reduction. so B must have only 1/4 of the pressure of A.

A quiet radio has an intensity level of about 40 dB. Busy street traffic has a level of about 70 dB. How much greater is the intensity of the street traffic compared to the radio? A) About the same B) About 10 times C) About 100 times D) About 1000 times E) About 10,000 times Explain.

D) About 1000 times increase 10db: increase by factor of 10 increase 20 db: increase by factor of 100 increase by 30db: increase by factor of 1000

Three containers are filled with water to the same height and have the same surface area at the base, but the total weight of water is different for each. Which container has the greatest total force acting on its base? a) container 1 b) container 2 c) container 3 d) all three are equal Explain.

D) All three are equal Pressure at the bottom of each depends only on the height of the water above it. Being same for all containers. Total force is the product of the pressure times the area of the base, but because the base is also the same for all containers, teh total force is the same.

A string is clamped at both ends and then plucked so that it vibrates in a standing mode between two extreme positions a and b. Let upward motion correspond to positive velocities. When the string is in position c, the instantaneous velocity of points along the string: A) Is zero everywhere B) Is positive everywhere C) Is negative everywhere D) Depends on the location along the string explain.

D) Depends on the location along the string When the string is flat, all points are moving through equilibrium posiiton and are therefore at their max velocity. however, the direction depends on the location of the point. some points are moving upward rapidly, and some points are moving downward rapidly.

what type of wave is formed when a stone is dropped in a pond? A) Polarized B) Longitudinal C) Lateral D) Transverse E) Soliton wave explain.

D) Transverse Wave The molecules of water move up and down in the vertical direction when the wave travels in hroizontal directions along the water surface.

At a football game, the "wave" might circulate through the stands and move around the stadium. In this wave motion, people stand up and sit down as the wave passes. What type of wave would this be characterized as? A) Polarized B) Longitudinal C) Lateral D) Transverse E) Soliton wave explain.

D) Transverse wave the people are moving up and down, and the wave is traveling around the stadium. Thus, the motion of the wave is perpendicular to the oscillation direction of the people, transverse.

Consider a wave on a string moving to the right, as shown below. What is the direction of the velocity of the particle at the point labeled B? (B is in the middle of a rising line) A) Right B) Down right C) Down D) Up E) Zero

D) Up! the wave is moving to the right, so the particle at B has to start moving upward in the next instant of time.

In the previous question, the horn had a rest frequency of F0, and we found that your friend heard a higher frequency F1 due to the Doppler shift. The sound from the boat hits the cliff behind your friend and returns to you as an echo. What is the frequency of the echo that you hear? A) Lower than F0 B) Equal to F0 C) Higher than F0 but lower than F1 D) Equal to F1 E) Higher than F1 Explain.

E) Higher than F1 the sound wave bouncing of the cliff has the same frequence F1 as the sound hitting the cliff (what your friend hears). For the echo, you are now a moving observer approaching the sound wave of frequency F1, so you will hear an even higher frequency