If sanity and insanity exist, how shall we know the difference?

Abody of weight 60 kg is standing in a lift the lift going upward with a uniform velocity of 4.9 metre per second slows down and stops in two seconds then apparent weight of the body during the slow down process is

The air that we breath is made mostly of which gaseous molecule

An object is kept at 45 m high and how much time will it take to reach the ground