00:01
So on this problem, we have a person that has a weight of 150 pounds that runs up a height 15 feet, and he does this in four seconds.
00:18
And so here we want to find how much power is generated when he runs up the stairs.
00:24
And we also want to find the time it takes for a 100 -walt light bulb to create the same amount of energy.
00:34
So first, let's focus on the person.
00:39
We know that power is equal to the energy created divided by the time it takes.
00:49
So here, this person climbs all the way to the top, the person is at a certain height.
00:55
And the energy we can use here is gravitational potential energy, which is just the mass times gravity times the height, and then t we'll also.
01:06
Know and then notice that ng is just the weight of this person.
01:11
Let's plug in those numbers...