The force constant of a wire is $k$  and that of another wire is $2k.$ When both the wires are stretched through same distance, then the work done

A block of mass $1\,kg$ slides on a rough horizontal surface. If the speed of the block decreases from $10\,m/s$ to $8\,m/s$ , the thermal energy developed in this process .................. $\mathrm{J}$

How much energy produced in burning of $1\, kg$ coal ?

A chain is on a frictionless table with one fifth of its length hanging over the edge. If the chain has length $L$ and mass $M$, the work required to be done to pull the hanging part back onto the table is

A small bar starts sliding down on inclined plane forming an angle $\theta $ with the horizontal. The friction coefficient depends on the distance $x$ covered as $\mu  = kx$ , where $k$ is a constant. Find the distance covered by the bar till it stops

A particle of mass $m $ is moving in a horizontal circle of radius $r$  under a centripetal force equal to $ - K/{r^2}$, where $K$  is a constant. The total energy of the particle is