Question

Each piston of an engine makes a sharp sound every other revolution of the engine.

(a) How fast (in km/hr) is a race car going if its eight-cylinder engine emits a sound of frequency 543 Hz, given that the engine makes 2022 revolutions per kilometer?
(b) At how many revolutions per minute is the engine rotating?

Answer 1

a) v = 241.69
`(km)/(h)`

b) w = 8145
`(rev)/(min)`

Step-by-step explanation:

Knowing
`(1)/(2022) (km)/(rev)` and 1 rev = 4 sounds

`w = 543 (sounds)/(s) * (1 rev)/( 4 sounds)\\ w = 135.75 (rev)/(s)\\ v = (1)/(2022) (km)/(s) * 135.75 (rev)/(s) * (3600 s)/(1 h) \\v = 241.69 (km)/(h) \\w = 135.75 (rev)/(s) * (60 s)/(1 min)\\ w = 8145 (rev)/(min)`