Quiz 3 2022W Results for Duong Nguyen
Score for this quiz: 9 out of 9
Submitted Mar 31 at 11:43a.m.
This attempt took 43 minutes.
pts
Question 1
Imagine you tie an elastic rope to a wall and hold it under tension. You
then swing your arm up and down twice to produce two wave pulses. The
two pulses are separated by a distance s = 0.60 m, as illustrated in the
figure. Both pulses are symmetrical and completely identical. They travel
at a speed of v = 1.5 m/s. If the second (left) pulse is D = 9.1 m away from
the wall at time t = 0s, at what time will the rope be (temporarily) straight
again for the first time?
If you do not think this is possible, put 99 as your answer. Otherwise give
your time in seconds to three significant figures.
Correct!
5.8667
orrect Answer 5.87 margin of error +/- 5%
pts
Question 2
, In a concert, a solo violinist begins to play music at a steady 62 dB. Then
more violins join in. They all play at the same intensity, and the sound
intensity level is now 69 dB. How many violins are now playing?
(Round your answer to the nearest integer.) 5
Answer 1:
Correct! 5
pts
Question 3
The figure above shows a standing wave on a string that is oscillating at
178 Hz. If the length of the string is 0.84 m, what is the wave speed?
Give your answer in m/s to three significant figures.
Correct!
99.68
orrect Answer 99.7 margin of error +/- 5%
pts
Question 4
You are standing at a distance 4.5 m away from a fire alarm bell when it
starts ringing. In order to decrease the sound level in your ear by 6dB,
how far should you be away from the bell?
Score for this quiz: 9 out of 9
Submitted Mar 31 at 11:43a.m.
This attempt took 43 minutes.
pts
Question 1
Imagine you tie an elastic rope to a wall and hold it under tension. You
then swing your arm up and down twice to produce two wave pulses. The
two pulses are separated by a distance s = 0.60 m, as illustrated in the
figure. Both pulses are symmetrical and completely identical. They travel
at a speed of v = 1.5 m/s. If the second (left) pulse is D = 9.1 m away from
the wall at time t = 0s, at what time will the rope be (temporarily) straight
again for the first time?
If you do not think this is possible, put 99 as your answer. Otherwise give
your time in seconds to three significant figures.
Correct!
5.8667
orrect Answer 5.87 margin of error +/- 5%
pts
Question 2
, In a concert, a solo violinist begins to play music at a steady 62 dB. Then
more violins join in. They all play at the same intensity, and the sound
intensity level is now 69 dB. How many violins are now playing?
(Round your answer to the nearest integer.) 5
Answer 1:
Correct! 5
pts
Question 3
The figure above shows a standing wave on a string that is oscillating at
178 Hz. If the length of the string is 0.84 m, what is the wave speed?
Give your answer in m/s to three significant figures.
Correct!
99.68
orrect Answer 99.7 margin of error +/- 5%
pts
Question 4
You are standing at a distance 4.5 m away from a fire alarm bell when it
starts ringing. In order to decrease the sound level in your ear by 6dB,
how far should you be away from the bell?
