# Math Help - Coefficient of friction?

1. ## Coefficient of friction?

A rectangular mass of 45.6 kg slides with a constant velocity down a ramp that makes an angle of 17.8 degrees with the horizontal.

What is the magnitude of the frictional force between the ramp and the mass? What is the coefficient of kinetic friction?

2. Originally Posted by colerelm1
A rectangular mass of 45.6 kg slides with a constant velocity down a ramp that makes an angle of 17.8 degrees with the horizontal.

What is the magnitude of the frictional force between the ramp and the mass? What is the coefficient of kinetic friction?
system is in dynamic equilibrium ...

$f_k = mg\sin{\theta}$

$\displaystyle \mu_k = \frac{f_k}{N} = \frac{mg\sin{\theta}}{mg\cos{\theta}} = \tan{\theta}$