A block of mass 30 kg is pulled up a slope as shown in with constant speed by applying a force of 200 N parallel to the slope from the initial position A to the position B, (a)Calculate : (i)the work done by force in moving the block from A to B, and (ii)The potential energy gained by the block Take, g=10 m s^(-2) (b)Account for the difference in answers to parts (i) and (ii)

A block of mass 30 kg is pulled up a slope as shown in with constant s

1.	A block of mass 30 kg is pulled up a slope as shown in with constant speed by applying a force of 200 N parallel to the slope from the initial position A to the position B, (a)Calculate : (i)the work done by force in moving the block from A to B, and (ii)The potential energy gained by the block Take, g=10 m s^(-2) (b)Account for the difference in answers to parts (i) and (ii)
Answer» Solution :(a)Given :m=30 kg,F=200 N,AB=3 m and CB=1.5 m. (i)Work done by the force in MOVING the blockfrom A to B =Force `xx` displacemet in the direction of force or`W=FxxAB` `200 N xx3 m` =600 J (ii)The potential energy gained by the block U=mgh where h=CB=1.5 m `therefore U=30xx10xx1.5=450 J` (b)Out of the work done 600 J ,only 450 J is the useful work RAISES the potential energy of the block and the remaining work =600 J-450 J=150 J is spent against the force of friction between the block and the SLOPE which GETS converted into heat energy