00:01
In this problem, we are given that there is a 60 kg runner and he begins to slide when he's moving at a speed of 3 .9 meter per second.
00:15
And the coefficient of friction between the surfaces in contact, well, that's given as 0 .7.
00:23
And he slides so that his speed is zero right before he reaches the base.
00:29
So this runner would be sliding such that when he reaches the base, his tops.
00:37
So the final velocity, that's zero meter per second.
00:41
And we are required to determine the total mechanical energy which is lost due to the friction.
00:48
And according to this work energy theorem, we see that the network, whatever it's done, it's because of the friction here because that's only present.
00:56
And that network done will be equal to the change in character.
01:00
Kinetic energy and the work what is done by friction that's dissipated.
01:05
So we see that the change in kinetic energy that will give us the mechanical energy which is lost due to the friction and the change in kinetic energy that can be well computed by taking the final kinetic energy and from this we subtract the initial one.
01:20
So the final kinetic energy that's zero because it comes to stop and the initial kinetic energy will be half into mass into square of initial speed...