A body is projected up with a velocity 50ms-1 after one second if accelaration due to gravity disappears then body

Since upward motion of the body is retarded motion, from v = u - gt, after one second its velocity will be v = (50 -10 x 1)m/s = 40m/s, so when gravity disappears the body will continue to move up with constant velocity of 40m/s.