(i)[2]
Calculate the total work done by the forces shown in the diagram as $B$ moves through $20\,\mathrm{m}$.
(ii)[3]
Given that the coefficient of friction between the block and the plane is $\frac{5}{8}$, Find the block's weight.
Mathematics 9709 · AS & A Level · Energy, work and power
Energy, work and power — practice question
A block $B$ rests on a rough horizontal plane. As shown in the diagram, two horizontal forces of magnitudes $30\,\mathrm{N}$ and $40\,\mathrm{N}$ act on $B$; these make angles $\alpha$ and $\beta$ respectively with the $x$-direction. The block is travelling in the $x$-direction at constant speed. It is given that $\cos\alpha = 0.6$ and $\cos\beta = 0.8$.