Question

A launcher is used to launch a 3kg block across the floor. The launcher give the block a kinetic energy of 2.16J. The block comes to a stop after sliding 0.21m. Calculate the coefficient of friction between the block and the floor.

Answer 1

According to energy conservation principle, the kinetic energy was spent to overcome friction:

$$KE=\mu mgx,\\ \space\\ \mu=\frac{KE}{mgx}=\frac{2.16}{3\cdot9.8\cdot0.21}=0.350.$$