WEBVTT

1
00:00:00.000 --> 00:00:06.629
Here is the problem: Find the kinetic energy of a 2 kg object moving at 3 m/s.

2
00:00:07.079 --> 00:00:12.222
Use the kinetic energy formula, rearranged for the unknown, in SI units.

3
00:00:13.022 --> 00:00:14.984
Formula: kinetic energy.

4
00:00:15.434 --> 00:00:17.431
Substitute the known values.

5
00:00:18.231 --> 00:00:21.865
So the answer is kinetic energy KE equals 9 J.

6
00:00:22.315 --> 00:00:32.149
Kinetic energy grows with the square of speed: doubling v multiplies KE by four. It is never negative, and the speed found from KE is a magnitude.

7
00:00:32.949 --> 00:00:38.591
Substituted every value back into the formula: both sides agree, which checks out.