If the radio waves that are sent from the speed gun have a frequency of 400,000,002 Hz and the radio waves reflected off an approaching car have a frequency of 400,000,109 Hz, what is the speed of the car? (Hz is the SI unit of frequency, equal to cycles per second).

40.1 m/s or 144.36 km/h

Explanation:

The equation is (v=∆ f/f) x (c/2)

V is velocity

delta f is returned frequency minus intial frequency divided by the initial frequency

c is the speed of light in m/s divided by 2

v= (400,000,109 Hz - 400,000,002 Hz)/400,000,002Hz x (299,792,458 m/s)/2

with the invention of the automobile, the woman of the house could drive to the store and get groceries. women were also free to socialize more. during world war ii women were allowed to work in factories to the war effort and could drive to work or ride mass transit buses to their jobs.

probably not if net force is zero