Thank you for posting your question here at brainly. A mass of m moves with 2V towards in the opposite direction of a mass, 4m moving at a speed of V, the speed of m was 2/5V and the mass of 4m was 7.5V. I hope it helps.
Well, Harry, what you said is not necessarily true the way you said it.
But we know what you mean, and what you meant to say is true.
The Doppler effect is observed if there is relative radial motion
between an object and an observer <em><u>AND</u></em> if the object happens
to be putting out sound or light in the observer's direction.
Well you of course have different kinetic energies with the two speeds.
Kinetic energy = (1/2)*mass*velocity^2
The vehicle's mass is the same in both cases, so we can ignore that as well as 1/2 since it's a constant.
So we have (30)^2 vs (60^2)
which is 900 vs 3600
So having 60 mph compared to 30 mph is 4 times the kinetic energy.
