00:01
All right, so let's say we have the graph of kinetic energy versus position, and it looks like this, or maybe like this, where this little intercept is 5 meters, and this up here is 28 joules.
00:16
So we want to know what is the speed when it passes through negative 3 meters, when x is equal to negative 3.
00:22
Well, what we can tell is the force here is constant, because the force, due to the work energy theorem, is going to be the change in kinetic energy over the displacement.
00:30
So we can write this as like negative 28 joules over 5 meters.
00:38
So we'll just write as negative 5 .6 newtons.
00:42
That's the force.
00:43
And so the speed of the object through x equals negative 3, the change in kinetic energy should just be equal to the work done, which is the force times that displacement times delta x...