A block of mass 250 g slides down an incline of inclination$37°$ with a uniform speed. Work done against the friction as the block slides through 1.0 m is

Here force that slided the body with uniform speed against friction

$F=mg\sin \theta$

And $F-f_k=0\Rightarrow F=f_k=mg\sin \theta$

So work done by friction $f_k$

$\text{w}=\text{mg}\sin \theta \times \text{s}$

${\text{=250×10}}^{-3}\text{×}\text{10}\times \frac{3}{5}\times 1=\text{1}\text{.5}\text{J}$