Question

What is the kinetic energy of a 1.40 kg discus with a speed of 22.5 m/s?

Answer 1

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

                         = (1/2) (1.4 kg) (22.5 m/s)²

                         =    (0.7 kg)  (506.25 m²/s² )

                         =          354.375  kg-m²/s²  =  354.375 joules .

This is just the kinetic energy associated with a 1.4-kg glob of
mass sailing through space at 22.5 m/s.  In the case of a frisbee,
it's also spinning, and there's some additional kinetic energy stored
in the spin.