Question

Calculate the speed of an 90,000 kg airplane with a kinetic energy of one billion Joules.


What is the mass of a car that has a kinetic energy if 4,320,000 J moving at 23 m/s?

My answer to number 1= 149.07

second one- not sure.
I looked up the internet for formulas on finding mass and speed, (ik the KE formula)
Im just stuck on these two. I looked at my lesson and it had no explanation, only on finding KE

Answer 1

1. 0.5M*V^2 = KE.
0.5 * 90,000 * V^2 = 1*10^9 J. V = ?.
V = 149.07 J.

2. Use same formula as #1:
0.5M*V^2 = KE.
0.5M * 23^2 = 4.32*10^6 J. M = ?.

Answer 2

I have the same question and I’m stuck it would really help if someone knew the answer to number two