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

$$\text{ Given }:$$
$$\text{ m = 250 g,}\theta ={37}^{\circ },\text{ d = 1 m }$$

Here, R is the normal reaction of the block.

As the block is moving with uniform speed, $$f=\text{ mg }\sin {37}^{\circ }$$

So, work done against the force of friction,

$$W=\text{ fd }\cos 0^{\circ }$$
$$W=(\text{ mg }\sin {37}^{\circ })\times d$$
$$W=(0.25\times 9.8\times \sin {37}^{\circ })\times 1.0$$
$$W=1.5J$$