What do astronauts eat in space for instant energy? Describe that food.

How does an astronaut float in a space shuttle ?

What is food?

A free - floating astronaut 'P' pushes another free-floating astronaut 'Q' in space . The mass of P is greater than that of Q. The force exerted by astronaut P on astronaut Q will be _______ .

Why do we need instant energy ? Does glucose give that energy ? Explain .