Question

A block of mass 250 g slides down an incline of inclination ${37}^{\circ }$ with a uniform speed. Find the work done against the friction as the block slides through 1.0 m.

Answer 1

$m_b=250g,\theta ={37}^{\circ },S=1m$

frictional force, $f=\mu R$

$mgsin\theta =\mu R...\left(i\right)$

$mgcos\theta =R...\left(ii\right)$

So, work done aginst $\mu R$

$=\mu RSsin\theta$

$=mg\frac{3}{5}S$

$=250\times 9.8\times \frac{3}{5}\times 1=1.5$