Question

A block of mass 250 g slides down an incline of inclination 37° with uniform speed. Find the work done against friction as the block slides through 1m.

Answer 1

$$\begin{gathered} \mathrm{Given}: \\ m=250g,\mathrm{\theta }=37°,d=1\mathrm{m} \end{gathered}$$

Here, R is the normal reaction of the block.



As the block is moving with uniform speed,
$f=mg\sin 37°$

So, work done against the force of friction,
$$\begin{gathered} W=fd\cos 0° \\ W=(mg\sin 37°)\times d \\ W=(0.25\times 9.8\times \sin 37°)\times 1.0 \\ W=1.5\mathrm{J} \end{gathered}$$