## anonymous 4 years ago A 1.4 kg block slides across a rough surface such that it slows down with an acceleration of 1.25 m/s(squared). What is the coefficient of kinetic friction between the block and the surface? Help please. Show steps.

The force of friction is proportional to the normal force of the object. The constant of proportionality is the friction coefficient. In notation $F_{friction} = F_f = \mu N$ where $$\mu$$ = coefficient of friction. Now, the normal force is the the surface responding to the weight of the object, $Weight = mg = N$ Using all that, we see that the force of friction is given by $F_f = \mu m g \ \ \ -- (1)$ On the other hand, friction is the only force acting on the block, hence $F_{net} = F_f = ma \ \ \ -- (2)$ You know the acceleration rate. Now use equations (1) and (2) to find $$\mu$$.