# Physics 141 FINAL

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1. The force of friction between two objects is

A. always opposite in direction to their relative motion
B. neither A or B is correct
C. both A and B are correct
D. creates heat from mechanical energy
A. always opposite in direction to their relative motion
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2. When a conventional car is braked to a stop, its kinetic energy is transformed to

A. stopping energy
B. heat
C. energy of motion
D. potential energy
B. heat
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3. At the do it yourself car wash on Route 17 you can have 3 minutes of "high pressure spray" to clean your vehicle. What is the pressure of the water when it hits your shiny fenders?

A. Between one and three atmospheres, depending on the velocity of water in the hose and Bernoulli's principle
B. Can't be determined without knowing the strength of the electric pump
C. One atmosphere (100,000 Pa). The extra pressure from the machine was converted to velocity when the water exited the nozzle
D. Three atmospheres (300,000 Pa) which was determined by gravitational potential energy and the 20m height of the water tower that pressurizes our water supply.
C. One atmosphere (100,000 Pa). The extra pressure from the machine was converted to velocity when the water exited the nozzle
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4. Which temperature scale has 373 degrees as the boiling point of water?
A. Fahrenheit
B. Centigrade
C. Kelvin
D. Celsius
C. Kelvin
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5. The maximum speed a practical single stage rocket can achieve is
A. less than the speed of its exhaust plume
B. equal to the speed of its exhaust plume
C. the speed of light
D. greater than the speed of its exhaust plume but less than is required for most satellite launches
D. greater than the speed of its exhaust plume but less than is required for most satellite launches
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6. To make an airplane fly upside down the pilot must:
A. use panels on the wings called flaps to change the wing shape for "inverse" lift
B. slow the airplane to reduce its Reynold's number
C. stand on the gas and pray
D. point the nose of the plane slightly up to create a positive angle of attack on the "wrong" side of the wing
D. point the nose of the plane slightly up to create a positive angle of attack on the "wrong" side of the wing
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7. When your house was new the clean copper pipes could deliver a generous flow of water to the shower. A decade later calcium deposits have reduced the inside diameter of the pipes and the shower feels weaker because:
A. the calcium deposits are rough and increase the friction that slows the flow
B. the flow in the pipe has increased its Reynolds number above 5,000 and the flow is turbulent
C. this is an illusion. the flow is unchanged as long as the pipe is at least partially open
D. the water must flow faster through the smaller opening in the pipe. since it has more kinetic energy it has less available pressure potential energy to drive the shower
D. the water must flow faster through the smaller opening in the pipe. since it has more kinetic energy it has less available pressure potential energy to drive the shower
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8. The fastest types of racing cars, Formula 1 and Indy cars, have wings attached to them to increase the downward force on their wheels and thus increase traction. The wings generate:
A. laminar flow
B. only lift
C. both drag and lift
D. mostly drag
C. both drag and lift
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9. You are floating along in a hot air balloon. You look up and notice that the bottom of the balloon is open. Although there is a minor loss of hot air due to the diffusion of molecules, the majority of the hot air remains inside the balloon despite this opening because
A. hot air has more inertia than cold air and doesn't accelerate easily
B. the air pressure inside the balloon's opening is the same as the air pressure outside that opening
C. hot air has a lower pressure than cold air, so hot air is drawn into the balloon by the partial vacuum inside it
D. the propane burner located below the opening keeps pushing the hot air back into the balloon
B. the air pressure inside the balloon's opening is the same as the air pressure outside that opening
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10. One of the most effective strokes in tennis is the top spin serve, in which the top of the ball spins away from the player who hit it. Which way is the lift force on this ball directed? (from p201 of your text)
A. upward
B. sideways and horizontal
C. downward
D. toward the player who hits it
C. downward
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11. The principal advantage of sending electric power across country on very high voltage transmission lines is that
A. these transmission lines are less likely to get in the way than low voltage transmission lines - which are much closer to the ground
B. they carry less energy per charge than low voltage transmission lines
C. they carry much more current than low voltage transmission lines
D. electric power lost in the wires is greatly reduced
D. electric power lost in the wires is greatly reduced
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12. It is a warm summer day and you are having lunch outdoors on a patio. A window air conditioning unit hums quietly nearby as it cools an office inside the building. Your friend notices that the unit's outdoor part is emitting a considerable amount of heat and comments on how strange that is. You explain correctly that the air conditioner's outside part is emitting the heat
A. it removes from the inside air and the heat it produces from the electricity it consumes
B. that is left over when it converts thermal energy from the inside air into electricity
C. it produces during its defrost cycle; when it warms up its evaporator to remove ice that forms because of the humidity
D. it produces only from the electricity is consumes
A. it removes from the inside air and the heat it produces from the electricity it consumes
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13. Household electricity in the USA is
A. 12 volt direct current
B. 120 volt direct current
C. 12 volt alternating current
D. 120 volt alternating current
D. 120 volt alternating current
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14. Can an electric current produce a magnetic field?
A. you can't tell without more information
B. a current will produce a magnetic field if it is greater than 5 Amps
C. yes, a current always produces a magnetic field
D. no, a current never produces a magnetic field
C. yes, a current always produces a magnetic field
(this multiple choice question has been scrambled)
15. Which of the following is a fundamental unit in the MKS system?
A. gram
B. second
C. kilometer
D. centimeter
B. second
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16. Which of the following is a scalar quantity?
A. position
B. angular momentum
C. linear momentum
D. energy
D. energy
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17. Using precise physics definitions, President Obama has energy when:
A. he is flying in Air Force One
B. he gives momentum to the Government Medical Care plan
C. he is directing a drone strike from the Situation Room
D. he electrifies and audience with his oratory
A. he is flying in Air Force One
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18. How much momentum do the CNU Captains have when they are gathered for the coach's briefing after they have defeated three consecutive football teams? Assume the CNU team roster includes 45 players with an average mass of 85 kg.
• 0.0 kg m/s2
• P=mv
19. Which of Newton's Laws is most responsible for your professor's ability to jerk a table cloth out from under a full coffee cup without spilling its contents?
A. 3rd law (action and reaction)
B. 1st law (inertia)
C. 2nd law (F=ma)
B. 1st law (inertia)
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20. Why does a hockey player continue to glide straight ahead even though he is not pumping his legs?
A. he has both linear and angular momentum and it takes the ice a long time to do enough work to transfer the momentums away
B. he has gravitational potential energy and the friction with the ice is insufficient to eliminate it
C. he has angular momentum that must be conserved
D. he has linear momentum and the force of the ice is small so it takes a long time to produce enough total impulse to transfer this momentum elsewhere
D. he has linear momentum and the force of the ice is small so it takes a long time to produce enough total impulse to transfer this momentum elsewhere
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21. When is your car not accelerating?
A. when you round an exit ramp at constant speed
B. when you are speeding down a straight stretch of I-64 at 80 mph
C. when you brake to avoid a skunk
D. when you leave an intersection after the light turns green
B. when you are speeding down a straight stretch of I-64 at 80 mph
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22. Bolts and screws are customarily made following the "right hand rule" for rotary motion. You want to tighten the screw that holds the cover plate on your dorm wall electric outlet. You should:
A. turn it counterclockwise
B. hit it with a hammer
C. turn it clockwise
d. none of the above
C. turn it clockwise
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23. It is much more damaging to be hit by a bullet than it is to be hit by the recoiling butt of the gun that fired it because:
A. the bullet carries more momentum than the gun
B. the momentum is unequally divided between the bullet and the gun
C. the bullet has more kinetic energy than the gun
D. high velocity transfers greater impulse
C. the bullet has more kinetic energy than the gun
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24. Both heavy and light bowling balls are available at the local lanes. If you push a heavy ball with the same force as a light one with half the heavy ball's mass, how much faster will the light ball accelerate?
A. four times as fast
B. twice as fast
C. it depends on how long you push
D. 9.8 m/s2
B. twice as fast
(this multiple choice question has been scrambled)
25. A 1.6 meter tall marksman can hit a target 1.6 meters high across a 100 meter wide flat field because
A. the bullet travels too fast to drop during flight
B. bullets fly "flat" because they are spinning rapidly from the gun's rifling
C. the gun barrel is pointed slightly upward to compensate for the inevitable effect of gravity
d. all of the above
C. the gun barrel is pointed slightly upward to compensate for the inevitable effect of gravity
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26. The antilock brake system in modern cars momentarily turns off braking power to individual wheels when the control system senses that a skid is imminent. Why does interrupting the braking force at a critical moment actually decrease the distance required to stop the car?
A. by momentarily reducing the brake force the system maintains dynamic friction and sustains a greater force between the individual tire and the road
B. reducing the braking force on one tire increases the braking forces on the others
C. the rapid brake pulses force the tire to dig into the pavement
D. by momentarily reducing the brake force the system maintains static friction and sustains a greater force between the individual tire and the road
D. by momentarily reducing the brake force the system maintains static friction and sustains a greater force between the individual tire and the road
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27. A force of 12N is required to pull a 4 Kg block across a level floor (which is NOT frictionless) to the right at a constant velocity. What is the magnitude of the frictional force?
A. greater than 12N, but less than 48N
B. you cannot tell without additional information
C. 12N
D. zero
C. 12N
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28. When cutting cardboard with scissors, why is it a good idea to move the cardboard as close as possibly to the scissors' pivot point?
A. there is a constant torque, so a small lever arm gives a large force
B. there is a bigger lever arm near the pivot
C. there is a bigger torque near the pivot
D. there is a larger force due to the smaller torque
A. there is a constant torque, so a small lever arm gives a large force
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29. You are trying to remove a stuck nut from a bolt. The bolt is in the vertical direction, so to remove the nut you get a wrench which will be turning in the horizontal plane. You realize that to be successful you must maximize the torque. Which of the following techniques will help you maximize the torque?
a. get a wrench with a longer handle
b. apply more force to the wrench
c. make sure you apply the force perpendicular to the wrench
d. all of the above will help maximize the torque
d. all of the above will help maximize the torque
30. When the springboard diver performs a multiple spin dive she:
A. stretches her body to increase her angular momentum
B. tucks her body to reduce her moment of inertia
C. stretches her body to increase her angular velocity
D. tucks her body into a ball to reduce her angular momentum
B. tucks her body to reduce her moment of inertia
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31. You are riding the decrepit elevator down from the second floor of Gosnold Hall to ground level. When the door closes the old machine lurches downward. What is true at that moment?
A. your mass and your instantaneous weight both remain the same
B. your mass briefly is reduced but your weight is unchanged
C. both your mass and your apparent weight are momentarily reduced
D. your mass stays constant but your weight is instantaneously reduced
D. your mass and your instantaneous weight both remain the same
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32. When we did the "shoot the professor" demo, why did the paintball stop without breaking?
A. by wearing the fluffy coats the professor maximized the forced applied to the paintball, and therefore he minimized the time over which the force was applied
B. by wearing the fluffy coats the professor maximized the time over which the force is applied to the paintball, and therefore he minimized the force which was applied
C. by wearing the fluffy coats the professor maximized the change in momentum that the paintball experienced
D. by wearing the fluffy coats the professor minimized the change in momentum that the paintball experienced
B. by wearing the fluffy coats the professor maximized the time over which the force is applied to the paintball, and therefore he minimized the force which was applied
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33. You want to position a bird feeder on a tree limb outside your window. However, the further you shinny out on the horizontal branch the risk that you will break the limb off the tree at the point it joins the trunk increases. Why?
A. you do additional work on the limb equal to your gravitational force times the distance from the trunk
B. your torque on the junction between the limb and the trunk increases as you move further out
C. the limb gets thinner and weaker out near the tip
D. you increase the force on the limb the further out you climb
B. your torque on the junction between the limb and the trunk increases as you move further out
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34. The handicap access ramp on a building near CNU takes a long route down the side of the building and even makes a right turn around the back before it reaches the pavement. Why didn't the builders make a shorter ramp without the awkward turn?
A. the longer ramp reduces the momentum the wheel chair must acquire to rise to the porch level
B. the longer ramp decreased the gravitational potential energy required to reach the porch
C. the longer ramp requires less force on the wheelchair to acquire the gravitational potential energy of the elevated porch
D. a shorter ramp would have violated the conservation of energy
C. the longer ramp requires less force on the wheelchair to acquire the gravitational potential energy of the elevated porch
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35. What part of your car can cause it to change its velocity without changing its speech?
A. nonsense, this is not possible
B. the brake pedal
C. the steering wheel
D. the gas pedal
C. the steering wheel
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36. When the total energy of a soccer ball includes both kinetic and potential energy you can be sure it is:
A. rising
B. falling
C. moving in some direction and in an elevated position
C. moving in some direction and in an elevated position
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37. Based on our class discuss, we know that high quality hold jewelry will be:
A. harder and more durable than impure gold
B. denser (more mass/volume) than a cheaper alloy
C. a deeper yellow color than low carat knockoffs
B. denser (more mass/volume) than a cheaper alloy
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38. Although a perfectly smooth golf ball (without aerodynamic dimples) will have a terribly short range its reduced lift will offer what advantage to an amateur player?
A. higher trajectory with steeply faced clubs (like a 9 iron or wedge)
B. reduced sideways curving flight ("slice")
C. more predictable putting
D. less felt shock in the club handle
B. reduced sideways curving flight ("slice")
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39. When one of the F-22 Raptor fighters as Langley AFB launches a rocket powered weapon, what does the missile push against to accelerate away from the airplane?
A. the air under the wing
B. its own exhaust (3rd law)
C. a spring system
D. the frame of the aircraft
B. its own exhaust (3rd law)
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40. Doubling the flow velocity in a water pipe will increase the kinetic energy of the stream by what factor?
A. half
B. two times
C. four times
D. it will not change
C. four times
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41. An astronaut is in orbit in the International Space Station. Which of the following statements is true?
A. the astronaut feels weightless because both she and the station are accelerating at the same rate
B. the astronaut has no mass because she is in space
C. there is not gravitational force of attraction on the astronaut by the earth
A. the astronaut feels weightless because both she and the station are accelerating at the same rate
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42. A curve ball pitch in baseball curves because of
A. drag forces
B. turbulent flow
C. laminar flow
D. lift forces
D. lift forces
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43. Archimedes principle states that the buoyant force exerted by a fluid on an object wholly or partially immersed in it is equal to
A. the volume of the fluid displaced by the object
B. the weight of the fluid displaced by the object
C. the weight of the object
D. the volume of the immersed object
B. the weight of the fluid displaced by the object
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44. Which fundamental law of physics provides the primary basis for Bernoulli's principle that pressure and velocity can be exchanged in a flowing fluid?
A. conservation of energy
B. Newton's third law (action and reaction)
C. the ideal gas law
D. conservation of momentum
A. conservation of energy
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45. Why does tennis ball not slow down very quickly when hit?
A. the fuzz causes turbulence that energizes the boundary layer of air
B. the Reynolds number is low, so the drag is small
C. the ball's aerodynamic shape makes a laminar wake behind the ball
D. the fuzz causes laminar flow in the boundary layer of air
A. the fuzz causes turbulence that energizes the boundary layer of air
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46. The driver of a ski boat can feel the effect of the skier's antics. When the skier turns hard to the left or right, the boat slows down slightly because:
A. the tow rope drags in the water during turns
B. the skier increased his drag when he generated the lift needed to accelerate him from side to side
C. the skier decreased his drag in the turn but he pulled the boat out of alignment with its path
D. the propeller of the boat increases its drag when it is loaded by the skier
B. the skier increased his drag when he generated the lift needed to accelerate him from side to side
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47. Pure turbo jet engines are fuel hogs compared to propellers because:
A. the jet imparts a bigger velocity change to a smaller mass flow of air to generate thrust
B. the jet has a much higher internal temperature, actually exceeding its melting point
C. the jet accelerates a bigger mass flow a smaller amount to generate thrust
D. the propeller is limited by the speed of sound
A. the jet imparts a bigger velocity change to a smaller mass flow of air to generate thrust
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48. The magnitude of the gravitational force that the earth exerts on the moon is ________ the magnitude of the force that the moon exerts on the earth?
A. impossible to calculate without more data
B. greater than
C. smaller than
D. the same as
D. the same as
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49. Why does the front edge of a Boeing 737's wing have a row of very small metal fins sticking straight up from the otherwise smooth surface? Think about sports balls.
A. to ensure laminar flow that reduces drag
B. to energize slow moving the boundary layer and delay flow separation from the wing
C. impossible to say without more data
D. to reduce the chance of bird strike damage
B. to energize slow moving the boundary layer and delay flow separation from the wing
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50. Physics terms are often incorrectly used in the popular press. Identify the error in this statement from the Discovery Channel: "Dirty Jobs" hero Mike Rowe is afraid of a shark that can bite with a force of 2000 pounds per square inch.
A. bite force should be specified in pounds, not pounds per square inch
B. bite damage is caused by kinetic energy not force
C. Mike Rowe is afraid of nothing
D. sharks exert torque not force with their jaws
A. bite force should be specified in pounds, not pounds per square inch
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51. Which of these men was NOT involved in the discovery of the motions of the planets?
A. Ferguson
B. Newton
C. Brahe
D. Kepler
A. Ferguson
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52. Noise canceling headphones widely advertised by Bose make an airplane ride seem quieter by producing additional sounds that:
A. form traveling waves
B. destructively interfere
C. constructively interfere
D. form standing waves
B. destructively interfere
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53. A child swinging on a playground swing set travels back and forth at a steady rate. What determines the period of the child's motion?
A. the combined mass of the child and the swing and the length of the chains
B. the combined mass of the child and the swing and the strength of earth's gravity
C. the ability of the child to "pump" the swing and the strength of earth's gravity
D. the strength of the earth's gravity and the length of the chains
D. the strength of earth's gravity and the length of the chains
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54. The foam "peanuts" commonly used for packing acquire a negative charge when they are emptied out the shipping container. The pesky things are hard to get rid of and insist on clinging to your arms because:
A. they transfer a positive charge to your body
B. the peanut charge polarizes the surface of your body and draws your positive charges near it
C. the moving charges of the peanut induce electric currents in your skin
D. your body has an equal distribution of positive and negative charges
B. the peanut charge polarizes the surface of your body and draws your positive charges near it
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55. Fast food joints keep their French fries under lamps that just have a slight reddish glow. These apparently feeble bulbs keep the food warm by:

a. convection of air. the bulbs have hot surfaces that warm the adjacent air and drive conventions currents across the greasy potatoes
b. conduction through the structure. the hot filaments in the bulbs heat the metal structure above the spuds. the metal sides and bottom of the food tray conduct this warmth to the fries
c. radiation. the lamps emit mostly invisible infrared light. these electromagnetic waves are absorbed by the fries and transfer heat to them
c. radiation. the lamps emit mostly invisible infrared light. these electromagnetic waves are absorbed by the fries and transfer heat to them
56. You are standing on a plastic bench that insulates you from your surroundings. Both you and the helium balloon you are holding are electrically neutral. You now rub the balloon against your sweater, so that the balloon becomes negatively charged, and then you let the balloon float away. You are left
A. electrically neutral
B. with a positive electric charge
C. with no negative electrically charged particles in your body
D. with a negative electric charge
B. with a positive electric charge
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57. Which of the following quantities is not conserved?
a. angular momentum
b. energy
c. momentum
d. entropy
d. entropy
58. Polar explorers typically choose light color parkas because:
A. they need to increase their transmission of the feeble available solar energy
B. they need the greatest reduction possible in convection heat loss
C. they want to minimize their conductive heat transfer
D. they want to reduce their radiation heat loss by lowering their emissivity
D. they want to reduce their radiation heat loss by lowering their emissivity
(this multiple choice question has been scrambled)
59. Electromagnetic waves have many characteristics in common with water waves, "Slinky" waves and sound waves. However, one unique feature of the electromagnetic waves that sets them apart is:
A. they obey a simple equation connecting velocity, wavelength and frequency
B. they can travel through vacuum
C. they have a wide spectrum of possibly frequencies
D. different technologies are needed to produce and detect them at different frequencies
B. they can travel through vacuum
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60. If the tires on your car wear unevenly the car may roll smoothly on city streets but it will start to shake as you pick up speed on the highway. The shaking seems to be really annoying at a certain speed but it appears to smooth out if you drive even faster. Why?
A. the tire vibrations are minimal at very high and low speeds. the car is simply responding to the amount of periodic vibration from the tire
B. the effect is an illusion. the vibration amplitude actually always increases as speed increases
C. the effect is an illusion. the car vibrates equally at all speeds
D. the suspension of the car has a resonant frequency. when the speed dependent shaking frequency of the lumpy tire hits this frequency the vibrations become terrible. at higher and lower speeds the tire vibrations have the wrong period to efficiently drive the resonance
D. the suspension of the car has a resonant frequency. when the speed dependent shaking frequency of the lumpy tire hits this frequency the vibration become terrible. at higher and lower speeds the tire vibrations have the wrong period to efficiently drive the resonance
(this multiple choice question has been scrambled)
61. The south pole of a permanent button style magnet will stick to a mild steel refrigerator door. The north pole of the same magnet will stick equally well to the same place on the refrigerator door because:
A. the microscopic domains in the soft steel of the door temporarily align to produce an opposite magnetic pole on the door surface. the opposite poles attract
B. the microscopic domains of the magnetically hard steel in the door can rapidly switch polarization to match the externally applied field of the button magnet
C. the steel in the door effectively redirects the button magnet's field to produce the attractive force. this attraction is north-south invariant
A. the microscopic domains in the soft steel of the door temporarily align to produce an opposite magnetic pole on the door surface. the opposite poles attract
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62. If you remove only one of the two wires connected to your car battery neither the lights nor the radio will work at all because:
A. the electrical parts of a car are wired in series. they go out like cheap Christmas lights when one is disconnected
B. removing a single wire closes the circuit and forbids current flow anywhere
C. removing one wire creates an open circuit for all of the electrical parts of the car
D. the radio and lights are wired in parallel and divide the available current into unworkably small amounts because of their parallel circuit configuration
C. removing one wire creates an open circuit for all of the electrical parts of the car
(this multiple choice question has been scrambled)
63. Water waves tend to hit parallel to the beach because of:
a. interference among different wavelengths in the complex wave
b. reflection of the previous wave redirects the next one parallel to the shore
c. refraction caused by slowing of the wave as it interacts with the shallows
c. refraction caused by slowing of the wave as it interacts with the shallows
64. Coulomb's law is similar to the universal law of gravitation in that
A. they both depend on mass
B. they have the same constant
C. they both depend on electrical charges
D. they are both inverse square laws
D. they are both inverse square laws
(this multiple choice question has been scrambled)
65. Can a magnetic field produce a current?
A. yes, it will always produce a current in a loop of wire near it
B. yes, it can produce a current in a loop of wire, but to do so the strength of the magnetic field must change or the orientation of the loop must change
C. no, it cannot produce a current in a loop of wire
B. yes, it can produce a current in a loop of wire, but to do so the strength of the magnetic field must change or the orientation of the loop must change
(this multiple choice question has been scrambled)
66. A piano has two or three strings that are struck simultaneously when each individual key is pressed. If these strings are not properly tuned to exactly the same pitch the sound will pulsate (change in intensity) as the key is held down. Why?
A. the sounds are reflecting around the inside of piano case
B. the slightly off pitch sounds refract in the sound board of the instrument
C. the notes from the individual strings resonate
D. the sound waves from the strings interfere, alternately destructively and constructively
D. the sound waves from the strings interfere, alternately destructively and constructively
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67. Why are the insides of thermos bottles typically shiny and metallic looking?
A. the shiny lining has a very low emissivity and keeps the radiation energy loss small
B. the metallic looking material has a lower thermal conductivity than cheaper glass and reduces conduction heat loss
C. the material used is simply stronger so it stays together better to keep in the heat
D. the shiny material is very smooth and seals tighter around the edges of stopper. this shuts down heat loss by convection
A. the shiny lining has a very low emissivity and keeps the radiation energy loss small
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68. What scientist championed alternating current and transformers as the technology basis of practical electric power distribution?
A. Nicholas Tesla
B. Thomas Edison
C. Michael Faraday
D. James Clerk Maxwell
A. Nicholas Tesla
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### Card Set Information

 Author: Melina.gonzales ID: 252493 Filename: Physics 141 FINAL Updated: 2013-12-11 22:31:17 Tags: physics 141 cueman exam final Folders: Description: ew physics no Show Answers:

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