The kinetic energy K of a particle equals
the amount of work required to accelerate the particle
from rest to speed V.It is also equal to the amount of
work the particle can do in the process of being brought
to rest. Kinetic energy is a scalar that has no direction in
space; it is always positive or zero. Its units are the same
as the units of work: 1 J = 1 N # m = 1 kg # m2>s2.