We have already described its momentum as
p = m v
Now we can describe its Kinetic Energy as
KE = (1/2) m v2
Momentum, p = m v, and Kinetic Energy, KE = (1/2) m v2, both describe the motion of an object. Both depend upon the object's mass and speed. However, Momentum and Kinetic Energy are not the same thing.
Momentum is a vector. The total momentum of a system could be zero even tho' individual parts have momentum.
Kinetic Energy is a scalar. Nothing "cancels it out". Energy can be changed from one form to another (including heat!).
(C) 2003, Doug Davis; all rights reserved