Calculate the kinetic energy of a rock that has a mass of 55 kg rolling down a hill with a velocity of 8 m/s.

The answer is 1760 J

Explanation:

Given:

m = 55 kg

v = 8 m/s

Unknown:

KE or kinetic energy of the rock

Formula and solution:

KE = 1/2 mv²

KE = 1/2 (55kg) (8 m/s)²

1/2 of 55kg = 55 ÷ 2 = 27.5kg

8² or 8×8 = 64 m²/s²

KE = (27.5kg) (64 m²/s²)

Final

KE = 1 760kg.m²/s² or simplify as 1760 J

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me

the right answer is 0.3 meters per second