00:01
In this problem, we have given a box of books is initially at rest at a distance d from the end of a wooden board.
00:07
Suppose this is a wooden board and this is the box of books.
00:13
This distance is capital d which is equal to 0 .540.
00:22
Now the angle of the board is increased slowly until the box just begins to slide.
00:30
So when this time box is just begin to slide, this angle is supposed theta.
00:43
So now in this case, we have to find the speed of the box when it reaches end of the board, when it reaches here.
00:58
Right.
01:00
In this problem, we have given the coefficient of static friction is 0 .3 to 0.
01:06
So, we know that when this box is in this position, one force is mg will be acting in this direction, and normal force in this upward direction, and friction force will be in this direction.
01:28
Initially, this friction force should be equal to mg sine theta so that it can start sliding.
01:42
So, we can say that the maximum value of static friction should be equal to mg sine theta.
01:53
And we know that here, this normal force should be equal to m g cost theta...