00:01
How much work is done by friction? our work done by friction, let's first draw our free body diagram.
00:08
We have our sled, our normal force, our tension force.
00:13
This component is m g sine of theta, and here is our weight component.
00:20
So our work done by friction is equal to negative mu k m g cosine of theta times our distance.
00:28
So we plug in our point one times seven 77 .5 times 9 .8 times cosine of 60 degrees times 31 .5 meters and we'll get our work done in joules.
00:41
So let's plug that into a calculator.
00:44
We're going to have our point 10 times 77 .5 times 9 .8 times cosine of 60 times 31 .5 to get 1196 .2 joules and that's with a negative sign.
01:03
Now for b, we'd like to find how much work is done over this distance, is done by the rope.
01:11
So we'd like to find our work done by the rope.
01:16
Now, we have our tension force equal to m g times sine of theta minus mu cosine of theta.
01:25
So let's first find this, 77 .5 times 9 .8 times sign of 60 minus 0 .100 cosine of 60 degrees.
01:35
So let's first find our tension.
01:39
77 .5 times 9 .8 times sine of 60 minus 0 .1 times cosine of 60 is 619 .7 newtons...