Friction Problem

[siralan]

The coefficient of friction between a certain brass block and a large revolving turntable is µ = 0.26. How far from the axis of rotation can the block be placed before it slides off the turntable if it is rotating at 33 1/3 rev/min?

:confused: :yuck: :frown: :grumpy: :surprised :rofl:

[Doc Al]

Consider that it is friction that supplies the centripetal force.

[gerben]

As long as the force that is needed to overcome friction is larger than the centripetal force the block will not move.

F_{friction} = F_z \mu = mg\mu
F_{centripetal} = \frac{mv^2}{r}

so you can move the block from the axis of rotation until these are equal, and when they are equal this holds:
mg\mu = \frac{mv^2}{r} \Leftrightarrow g\mu = \frac{v^2}{r}
and using v = r*v_{rotational} you can solve this