00:01
So in this question, we've got an individual doing a hamstring curl.
00:05
When you think of their knee is a pivot, and then their leg is a rod, and the length of the tibia is 0 .6 metres.
00:17
And we're told that the knee is flexed at an angle of 25 degrees above the horizontal.
00:25
And we've got a mass of 15 kilograms attached to the edge of the leg.
00:30
So this is m equals 15 kilograms.
00:35
So it's going to be applying a force here of m g.
00:43
So the length of the moment arm is going to be this length.
00:48
So l moment.
00:52
So question two.
00:55
L moment is going to be l times, and this i'm going to call this theta.
00:59
L times the cosine of theta because we want the perpendicular distance from the pivot, which is this distance here, l -sign theta, which is 0 .6 sine 25 meters, which i'll just put in my calculator now, 0 .6 sine of 25 degrees is, sorry, this should be cosine, cosign, not sign, my mistake, which is 0 .54 meters...