ΣW = ΔK = mvf2 / 2 - mvi2 / 2
Kinetic energy is a scalar and has the same units as work (i.e. Joule).
Note that if the mass of an object is increased, the increase in kinetic energy increases linearly; if the velocity of an object is increased, the increase in kinetic energy increases quadratically. For example, doubling the mass of an object doubles its kinetic energy; doubling its velocity quadruples its kinetic energy.
- Serway and Beichner, Physics for Scientists and Engineers, Fifth Edition