WEBVTT

1
00:00:00.000 --> 00:00:06.989
Here is the problem: Find the kinetic energy of a 70 kg object moving at 8 m/s.

2
00:00:07.439 --> 00:00:12.663
Use the kinetic energy formula, rearranged for the unknown, in SI units.

3
00:00:13.463 --> 00:00:15.344
Formula: kinetic energy.

4
00:00:15.794 --> 00:00:17.675
Substitute the known values.

5
00:00:18.475 --> 00:00:23.874
So the answer is kinetic energy KE equals 2240 J.

6
00:00:24.324 --> 00:00:34.193
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
00:00:34.992 --> 00:00:40.658
Substituted every value back into the formula: both sides agree, which checks out.