Consider an elliptical shaped rail in the vertical plane with and . A block of mass 1 kg is pulled along the rail from P to Q with a force of 18 N, which is always parallel to line PQ (see the figure given). Assuming no frictional losses, the kinetic energy of the block when it reaches Q is joules. The value of is (take acceleration due to gravity ) [2014]

(5)
Work done = Increase in P.E. + gain in K.E.