<span>Chemical and kinetic energy...</span>
You didn't actually include the speed of sound. But it doesn't matter for this question. If the trumpeter and the listener are on the same moving sidewalk then the distance between them is not changing. The Doppler shift only happens when the distance between the source and the Observer is changing. So the Listener hears the same 290 Hertz that the trumpeter is generating.
The initial momentum of the car is
(mass) x (speed) = 20,000 kg-m/s
"Impulse" is (force exerted) x (time the force lasts)
and it's equal to the change in momentum.
(Force) x (10 sec) = 20,000 kg-m/s
Divide each side by (10 sec) and you have
Force = (20,000 kg-m/s) / (10 sec)
= 2,000 kg-m/s² = 2,000 Newtons
Yes. Animals such as certain species of penguin and polar bear.
Figure out which is less harmful and continue to make sure he makes careful decisions while doing so.