Question

A particle is projected vertically up with​ a velocity 96m/s after 2s if the acceleration due to gravity ceases to act the velocity of body at the end of next 3s

Answer 1

The acceleration due to gravity ceases to act on the body after 2s, therefore the magnitude velocity will remain constant after 2s. So the velocity at the end of next 3s will be same as the velocity acquired till 2s(the time till gravity acts).
Velocity after 2s-
v=u+at

v=96-9.8(2)
[acceleration -g as it acts downwards]

v=76.4 m/s

Hope this helps.