00:02
Hi, here in this given problem there is a level ceiling, the two points over the ceiling, a and b, at a distance of 0 .5 meter and the two strings, the longer one and the shorter one.
00:26
The longer one, this is 0 .4 meter the shorter one, this is 0 .3 meter and a lamp has been hanging here.
00:38
Suppose the mass of the lamp is m so its weight mg will be acting vertically downward.
00:44
Now if we look for a pythagorean triplet here and consider this point to be c.
00:56
So these three sides of the triangle 0 .4 meters, 0 .5 meter and 0 .3 meter, these are making a pythagorean triplet.
01:17
These are making a pythagorean triplet here in which 0 .5 meter is the largest one.
01:40
And pythagorean triplet means the square of 0 .3 plus square of 0 .4 it is coming to be equal to the square of 0 .5.
01:53
That's why this is the pythagorean triplet.
01:55
Therefore angle c is 90 degree.
01:59
Now if we draw a vertical line here which will serve as the line of action of this weight m .g then now this angle will become a right angle triangle in which this angle may be found and using 10 theta is equal to perpendicular which will be 0 .4 upon base which will be 0 .3.
02:32
Means this is 1 .33.
02:40
So this angle theta will be given by 10 inverse 0 .33...