Author Question: A boy on a bicycle approaches a brick wall as he sounds his horn at a frequency 400 Hz. The sound he ... (Read 411 times)

clippers! · **on:** Jul 29, 2018

A boy on a bicycle approaches a brick wall as he sounds his horn at a frequency 400 Hz. The sound he hears reflected back from the wall is at a frequency 408 Hz.

At what is the speed is the boy riding his bicycle toward the wall? Assume the speed of sound in air is 340 m/s.
A)

3.68 m/s

B)

333 m/s

C)

6.67 m/s

D)

6.80 m/s

E)

3.37 m/s

Question 2

A 55-cm steel rod has a diameter of 30 cm. The compressive strength of steel is 500 106 N/m2. What is the compression force that would break the rod?

A)

3.5 107 N

B)

2.4 107 N

C)

1.4 108 N

D)

4.7 108 N

E)

8.9 108 N