You fire a paintball from a paintball gun straight up into the air at 25.0 m/s What is the instantaneous velocity at the top of its flight?

The instantaneous velocity at the top of its flight is  v = 0 m/s

Explanation:

From the question we are told that

   The  initial velocity is u = 25.0 m/s

Generally an  instantaneous velocity can be defined as the velocity of an object at an instant of  time period during its motion, , generally the velocity of a object at it maximum height is  0 m/s hence the  instantaneous velocity of the paintball at the top of its flight is  0 m/s

found in the nucleus

has mass of one amu

the answer would be a