00:01
So here we know that in the absence of friction, we have a simple conversion of energy between the kinetic form and the potential form.
00:09
So here along the horizontal plateaus, there is friction, however, that causes some of the kinetic energy to dissipate according to equation 831.
00:21
So essentially, we know that here the coefficient of kinetic friction is equaling 0 .50.
00:30
And we know that the force normal is equaling mg.
00:33
So after it slides down a vertical distance d, we can say that its kinetic energy would be equal to one -half mv squared.
00:42
This is equaling m -g -d after it slides down a distance d.
00:49
And then some of which is converted to thermal energy.
00:54
And this would be equal to the coefficient of kinetic friction times m -g -d.
01:01
So the value of kinetic energy at the end of the first point, plateau, just before it starts descending towards the lowest plateau, this is going to be k equaling mgd minus the coefficient of kinetic friction, mgd, which is essentially equalling because the coefficient of kinetic friction is 0 .5, this would essentially be equal to one -half mgd.
01:28
Now, in its descent to the lowest plateau, it gains mgd divided by two more kinetic energy.
01:35
But as it slides across that lowest plateau, it loses, again, mu -sub -k -m -g -d over 2 of that...