Question

A block of mass 100 g slides on a rough horizontal surface. If the speed of the block decreases from 10 m $s^{-1}$ to 5 m $s^{-1}$, find the thermal energy developed in the process.

Answer 1

Thermal energy developed.

= Change in K.E.

= $\frac{1}{2}\times \frac{100}{1000}\times 100-\frac{1}{2}\times \frac{100}{1000}\times 25$

= 5- $\left(\frac{5}{4}\right)=\frac{15}{4}$ = 3.75 J