It is easier to roll a stone up a sloping road than to lift it vertical upwards becauseA.work done in rolling is more than in liftingB.work done in lifting the stone is equal to rolling itC.work done in both is same but the rate of doing work is less in rollingD.work done in rolling a stone is less than in lifting it

A single cylinder, single acting, four stroke gas engine develops 20 kW at300 r.p.m. The work done by the gases during the expansion stroke is three times the work done onthe gases during the compression stroke, the work done during the suction and exhaust strokesbeing negligible. If the total fluctuation of speed is not to exceed ± 2 per cent of the mean speed andthe turning moment diagram during compression and expansion is assumed to be triangular inshape, find the moment of inertia of the flywheel.

vector a=4x-3y and vector b=2x+6y. What is the magnitude and direction of vector c=b-2a