Kinetic Energy = (1/2) (mass) (speed)² .
Just take that formula, write "30" in place of 'mass', write "20" in place
of 'speed', then do the arithmetic on the right side and you'll have the
kinetic energy. When all the measurements are in SI units, you can
do that.
(Don't forget about the ' 1/2 ', and don't forget to square the speed.)
