Physics Test 2 (B)

10) A 5-kg fish swimming at a speed of 1 m/s swallows an absent-minded 1-kg fish at rest. The speed of the larger fish after this lunch is

5/6 m/s.

19) Using 1000 J of work, a toy elevator is raised from the ground floor to the second floor in 20 seconds. The power needed to do this job was

50 W

32) An object that completes 10 vibrations in 20 seconds has a frequency of

0.5 hertz.

50) For FM radio, the F stands for

frequency

14) A job is done slowly, while an identical job is done quickly. Both jobs require the same amount of work, but different amounts of

power

46) Reverberation is a case of

re-echoed sound.

2) A rifle recoils while firing a bullet. The speed of the rifle's recoil is small because the

rifle has much more mass than the bullet.

26) A torque acting on an object tends to produce

rotation.

38) A child swings back and forth on a playground swing. If the child stands rather than sits, the time for a to-and-fro swing is

shortened.

48) The object with the highest natural frequency is a

small bell.

45) The speed of a sound wave in air depends on

the air temperature.

37) A floating object oscillates up and down 2 complete cycles in 1 second as a water wave of wavelength 5 meters passes by. The speed of the wave is

10 m/s.

22) A machine puts out 100 Watts of power for every 1000 Watts put into it. The efficiency of the machine is

10%.

42) The approximate range of human hearing is

20 hertz to 20,000 hertz.

9) A 1000-kg car moving at 10 m/s brakes to a stop in 5 s. The average braking force is

2000 N.

4) A 4 kg ball has a momentum of 12 kg m/s. What is the ball's speed?

3 m/s

20) A TV set is pushed 2 m with a force of 20 N. How much work is done on the set?

40 J

23) A moving object has

A) momentum. B) energy. C) velocity. *D) all of these

44) Sound waves cannot travel in

a vacuum.

33) A standing wave occurs when

a wave reflects upon itself.

28) The famous Leaning Tower of Pisa does not topple over because its center of gravity is

above a place of support.

24) A feather and a coin dropped in a vacuum fall with equal

accelerations.

11) You're driving down the highway and a bug bounces off your windshield. Which undergoes the greater change in momentum during the time of contact?

both the same

27) Toss a baseball bat into the air and it wobbles about its

center of mass.

30) A car travels in a circle with constant speed. The net force on the car is

directed towards the center of the curve.

25) Your pet hamster sits on a record player whose angular speed is constant. If he moves to a point twice as far from the center, then his linear speed

doubles

34) A Doppler effect occurs when a source of sound moves

either towards you or away from you.

35) A bow wave is produced when a wave source moves

faster than the waves it produces.

17) A clerk can lift containers a vertical distance of 1 meter or can roll them up a 2 meter-long ramp to the same elevation. With the ramp, the applied force required is about

half as much

36) If you double the frequency of a vibrating object, its period

halves.

21) When a car is braked to a stop, its kinetic energy is transformed to

heat

7) A karate expert executes a swift blow and breaks a cement block with her bare hand. The magnitude of the force experienced by her hand is

identical to the force applied to the block

39) If at a concert you run toward the orchestra, the frequency of the sound you hear will be

increased.

29) When a twirling ice skater brings her arms inward, her rotational speed

increases.

49) The phenomenon of beats results from sound

interference

43) A sound wave is a

longitudinal wave.

12) If a monkey floating in outer space throws his hat away, the hat and the monkey will both

move away from each other, but at different speeds.

16) An object that has kinetic energy must be

moving

40) A sound source of high frequency emits a high

pitch.

1) It is correct to say that impulse is equal to

the change in momentum.

6) A heavy truck and a small car rolling down a hill at the same speed are forced to stop in the same amount of time. Compared to the force that stops the car, the force needed to stop the truck is

the same

31) In a longitudinal wave the compressions and rarefactions travel in

the same direction.

18) The ball rolling down an incline has its maximum potential energy at

the top

3) In order to catch a ball, a baseball player extends the hand forward before impact with the ball and then lets it ride backward in the direction of the ball's motion. Doing this reduces the force of impact on the player's hand principally because the

time of impact is increased.

13) If you push an object twice as far while applying the same force, you do

twice as much work.

15) If an object is raised twice as high, its potential energy will be

twice as much.

41) A common source of wave motion is a

vibrating object.

47) Sound will be louder if a struck tuning fork is held

with its base against a tabletop.

5) Recoil is noticeable if we throw a heavy ball while standing on roller skates. If instead, we go through the motions of throwing the ball but hold onto it, our net recoil will be

zero

8) Two billiard balls having the same mass and speed roll toward each other. What is their combined momentum after they meet?

zero ( total momentum stays the same)