00:01
So in this question, we're trying to find out the tension in the string when the pendulum bob is at its lowest point.
00:07
So what we can use in this question is the conservation of energy.
00:12
So we know that the initial gravitational potential energy is equal to the final kinetic energy.
00:20
If we take the gravitational potential energy to be zero at the lowest point, we can just set this to help our calculations be easier.
00:27
So the first step is to work out this change in height so that we can calculate the change in gravitational potential energy.
00:34
So we know the length of the string is 0 .5 meters, and we know this angle is 37 degrees.
00:40
So we can work out this length here by doing 0 .5 cos 37, as this is the adjacent length.
00:49
So 0 .5 cos 37 is equal to 0 .4 meters.
01:06
So this gives us this length...