The sun produces energy by converting gravitational potential energy into radiation via quantum processes in the nucleus of the atoms.
Since the mass of the sun and it's temperature are not quite enough to generate nuclear FUSION on their own, quantum tunneling is the primary process by which nuclear fusion occurs in our sun, SOL. FISSION also occurs as a result of this fusion.
Additionally, gravitational potential energy is also the reason that supernovae are so bright. Cool!
3 is the answer to your question
Answer
given,
frequency from Police car= 1240 Hz
frequency of sound after return = 1275 Hz
Calculating the speed of the car = ?
Using Doppler's effect formula
Frequency received by the other car
..........(1)
u is the speed of sound = 340 m/s
v is the speed of the car
Frequency of the police car received
now, inserting the value of equation (1)
1.02822(340 - v) = 340 + v
2.02822 v = 340 x 0.028822
2.02822 v = 9.799
v = 4.83 m/s
hence, the speed of the car is equal to v = 4.83 m/s