Author Question: As you stand by the side of the road, a car approaches you at a constant speed, sounding its horn, ... (Read 39 times)

K@ · **on:** Jul 29, 2018

As you stand by the side of the road, a car approaches you at a constant speed, sounding its horn, and you hear a frequency of 80.0 Hz.

After the car goes by, you hear a frequency of 60.0 Hz. What is the speed of the car? Assume that he speed of sound in air is 343 m/s.
A)

64 m/s

B)

49 m/s

C)

16 m/s

D)

36 m/s

E)

25 m/s

Question 2

The tensile strength for a certain steel wire is 3000 MN/m2. What is the maximum load that can be applied to a wire with a diameter of 3.0 mm made of this kind of steel?

A)

64 kN

B)

9.0 kN

C)

42 kN

D)

85 kN

E)

21 kN