# What is the minimum angle?

1. Jun 3, 2010

### physics_freak

1. The problem statement, all variables and given/known data

A box with mass of 45 kg is placed on a flat board. It starts moving when the board is inclined at 27 degrees. If the mass is doubled, what is the minimum angle needed so that it starts moving?

2. Relevant equations

Frictional force = mgsin$$\theta$$

3. The attempt at a solution

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2. Jun 3, 2010

### PhanthomJay

Your (or is it the book's?) solution is correct.