A body of mass 1 kg is moving in a vertical circular path of radius 1 m. The difference between the kinetic engeries at the highest and lowest position is

A body of mass 1 kg is moving in a vertical circular path of radius 1

1.	A body of mass 1 kg is moving in a vertical circular path of radius 1 m. The difference between the kinetic engeries at the highest and lowest position is
Answer» 20 J 10 J `4sqrt(5)J` `10(sqrt(5)-1) J` Solution :Here , `m = 1 kg , r = 1m` Velocity at the lowest point, `v_L = sqrt(5 gr)` Velocity at the HIGHEST point , `v_H = sqrt(gr)` Difference in kinetic ENERGY = `1/2 m[v_L^2 - v_H^2]` `= 1/2 m[(sqrt(5 gr))^2 - (sqrt(gr))^2] = 2 mgr = 2 xx 1 xx 10 xx 1 = 20 J`.