Question

I dont know how to find the average angle if repose

Answer 1

We are asked to determine the angle of repose given the coefficient of static friction. To do that we will use the following relationship:

`\tan \theta=\mu_s`

Where:

`\begin{gathered} \theta=\text{ angle of repose} \\ \mu_s=\text{ coefficient of static friction} \end{gathered}`

We solve for the angle of repose by taking the inverse tangent function:

`\theta=\tan ^(-1)(\mu_s)`

Now we substitute the first value:

`\theta=\tan ^(-1)(0.25)=14.04`

For the second value we get:

`\theta=\tan ^(-1)(0.5)=26.57`

Therefore for the first surface pairs, we have angles of repose: 14.04 - 26.57