Question

A car has a kinetic energy of 1.9 * 103 joules. If the velocity of the car is decreased by half, what is its kinetic energy?

Answer 1

kinetic energy =(.5)*m*(v^2)

Answer 2

so if before you had 1.9*10^3=(.5)m(v^2)
and now you are using v/2
new kinetic energy = (.5)*m*(v/2)^2=(.5)*m*(v^2)/4