Q.

A lift of mass M = 500 kg is descending with speed of 2 m s-1. Its supporting cable begins to slip thus allowing it to fall with a constant acceleration of 2 m s-2. The kinetic energy of the lift at the end of fall through a distance of 6 m will be ________ kJ.                 [2023]


Ans.

(7)

v2=u2+2as=22+2(2)(6)

      =4+24=28

KE=12mv2=12(500)(28)=7000 J=7 kJ