Asked by poojachandra | 11th Feb, 2010, 04:17: PM

Expert Answer:

Dear student,

Consider a body placed on a platform whose angle with the horizontal can be changed for e.g., a tipper with stones at the back. Only when the platform is raised to a certain angle do the stones begin to slide down. This is because the component of gravitational force along the platform just overcomes the frictional force. This angle to which the platform is inclined with the horizontal, is called the angle of sliding or the angle of repose.

Let us see the mathematical aspect of it. Consider the second figure .

The weight W can be resolved into two rectangular components. W cos f and W sin f. The component W cos f balances the normal reaction R while the component W sin f is equal to the limiting friction flimiting.

We notice that the angle of repose or sliding and the angle of friction are both equal.

Hope this helps.

Answered by  | 11th Feb, 2010, 06:01: PM

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