A body of mass $2 \mathrm{kg}$ starts with an initial velocity $5 {\mathrm{ms}}^{-1}.$ If the body is acted upon by a time dependent force $\left(F\right)$ as shown in figure, then work done on the body in $20 \mathrm{s}$ is

A body of mass $m$ was slowly pulled up the hill by a force $F$ which at each point was directed along the tangent of the trajectory. All surfaces are smooth. Find the work done by this force

A particle is placed on the top of a hemispherical shell of same mass. Shell is free to move on the smooth ground. If particle is given a gentle push and reaches to angular position $q$ as shown in figure then for an observer fixed on a shell, ratio of reaction force exerted by shell to pseudo force (as observed from shell) acting on particle, is

Consider the system shown in the figure. Coefficient of friction between the block and table is $\mu =0.5.$ The system is released from rest. Find the work done by friction, when the speed of block is $10 {\mathrm{ms}}^{-1}(m=1 \mathrm{kg})$