Question

what is the kinetic energy of a 1-kilogram ball is thrown into the air with an initial velocity of 30 m/sec

Answer 1

Kinetic energy = (1/2) (mass) (speed)²

KE = (1/2) (1 kg) (30 m/s)²

KE = (1/2) (1 kg) (900 m²/s²)

KE = 450 kg-m²/s²

KE = 450 Joules

That's at the instant it leaves the thrower's hand.  After that, gravity immediately begins to rob its kinetic energy, so the KE starts decreasing right away.