# What is the angular range for #theta#, for which the masses will not move in the following diagram?

##### 1 Answer

First considering the situation when the block **A** tends to move downward along the inclined plane.In this situation the force of friction as well as weight of block **B** together will balance the downward force on block **A**.

Taking acceleration due to gravity

So

Let 10/sqrt109=cosalpha and 3/sqrt109=sinalpha#

This means

The above equation becomes

Again considering the situation when the block **A** tends to move upward along the inclined plane.In this situation the force of friction as well as downward force on block **A** together will balance the downward force on block **B**.

So

Similar manner we get

Here

So when