Question

How to calculate kinetic energy of a projectile at the highest point of a projectile?

Answer 1

Kinetic energy is half the product of the mass and the square velocity and at highest point the velocity is 0 thus the kinetic energy is 0 J

Answer 2

For a projectile the total energy is equal to the kinetic energy that is 1/2 mv and the the potential energy mgh that add. Initially the total energy is all kinetic energy at the highest point the energy is all potential.so kinetic energy at that point is 0.
hope it helps