Final Exam Practice Exam

The figure shows a snapshot of a wave at a given instant of time. The frequency of this wave is 120Hz. What are the (a) amplitude, (b) wavelength, (c) speed of the wave

(a) 0.10 (height of graph) (b)0.20 (one period.... distance before graph repeats again) (c) Frequnecy * wave length= 24 m/s

A leaky faucet drips 40 times in 30s. what is the frequency of the dripping?

1.3 Hz f=40/30

A fisherman fishing from a pier observes that the float on his line bobs up and down, taking 2.4 s to move from its highest points to its lowest points. he also estimates that the distance between adjacent wave crest is 48. What is the speed of the waves going past the pier?

10 m/s T=2(2.4s)=4.45 N=Tf=T/t=48/(2*2.45)=10m/s

If the amplitude of the motion of simple harmonic oscillator is doubled, by what factor does the maximum speed of the oscillator change?

2 Nmax=2*pi*f*A

A quartz crystal in a digital watch has a frequency of 32.8 kHz. What is its period of oscillation?

30.5 µs T=1/f=1/32.8X10³

What is the frequency of a pressure wave of wavelength 2.5m that is revealing at 1400 m/s?

560 Hz

At what minimum rate is a 60.0-kg boy using enerby when its 8.00 s, he runs up a flight of stairs that is 10.0m high.

735 W p=∆u/∆t=mgh/∆t

In a physical fitness program, a women weights 510N runs up four flights of stairs in 22s. Each flight rises 3.1 m. (a): what is her total change of potential energy? (b): What was the minimum average power in watts that she expended during 22s?

A) ug=mgh=6.3 kJ B)P=∆w/∆t=6300J/22s=286W

Seven seconds after a brilliant flash of lighting, thunder shakes the house. Approximately how far was the lighting strike from the house?

About two Kilometers away. N=∆x/∆t ∆x=N∆t 343 m/s*7s =2401 m

T/F: A person stands on the edge of a cliff. She throws three identical rocks with the same speed. Rock X is thrown vertically upward, rock Y is thrown horizontally, and rock Z is thrown vertically downward. If the ground at the base of the cliff is even, Rock Z hits the ground with the greatest speed if there is no air resistance?

False

T/F: If a stone is dropped with an initial gravitational potential energy of 100J but reaches the ground with a kinetic energy of only 75J, this is a violation of the principle of the conversation of energy.

False

T/F: Jill does twice as much work as jack does in half the time. Jill's power output is the same as Jack's power output.

False, P=w/t

T/F: A heavy lead block and a light aluminum block of equal sizes are both submerged in water. The buoyant force is greater on the lead block.

False, same size

T/F: if we double the frequency of a system undergoing simple harmonic motion, the period is doubled

False, t=1/f

T/F: A hollow sphere of negligible mass and radius R is completely filled with a liquid so that its density is p. You now enlarge the sphere so its radius is 2R and completely fill it with the same liquid. the density of the enlarged sphere is 8p.

False..p=mn

What is the wavelength of the wave shown in the figure?

It cannot be determined from the given information

A mass on a spring undergoes SHM. When the Masses is at its maximum distance, from the equilibrium position. which of the following statements about it are true?

Its speed is zero

What is the frequency of the wavelength shown in the figure?

Period T=2s f=1/t=A

When a 0.350kg package is attached to a vertical spring and lowered slowly, the spring stretches 12.0cm. The package is now displaced from its equilibrium position and undergoes simple harmonic oscillation when released. When is the period of the oscillations?

T=2*pi* sqrt m/k 0.695 s

T/F: A bead is moving with a speed of 20m/s at position A on the track is shown in the figure. This track is friction-free, and there is no appreciable air resistance. The speed of the bead at point C is greater than at point A?

True

T/F: An object is attached to a vertical spring and bobs up and down between points A and B. The elastic potential energy is a minimum midway between A and B

True

In simple harmonic motion, when is the speed the greatest? (There could be more than one correct choice)

When the magnitude of the acceleration is a minimum When the potential energy is zero

A sewing machine needle moves up and down in simple harmonic motion with an amplitude of 1.27cm and a frequency of 2.55 Hz. What are the (a) maximum speed and (b) maximum acceleration of the tip of the needle

amax=(2*pi*f)²A=326 cm/s² Nmax=2*pi*f*A=20.3 cm/s

A string of mass, m, is under tension, and the speed of a wave in the string is ,v,. What will be the speed of a wave in the string if the mass of the string is increased to 2m but with no change in the length or tension?

v/Srt2 n=(Fs/m)^1/2 m=m/2