Question

A vehicle of mass `15` quintal climbs up a hill `200 m` high. It then moves on a level road with a speed of `30 ms^(-1)`. Calculate the potential energy gained by it and its total mechanical energy while running on the top of the hill.

Answer 1

`m = 15 "quintal" = 1500 kg, g = 9.8 ms^(-2), h = 200 m`
P.E. gained, `U = mgh = 1500 xx 9.8 xx 200 = 2.94 xx 10^(6) J`
`K.E = (1)/(2) mv^(2) = (1)/(2) xx 1500 xx (30)^(2) = 0.675 xx 10^(6) J`
Total mechanical energy
`E=K +U =(0.675 + 2.94) xx 10^(6) = 3.615 xx 10^(6) J`.