1. Let us now look at the work done by a net force.  = 0 o, so cos  = 1 Maximum kinetic energy that an object can have. Change in kinetic energy due to a change from an initial velocity v 0 to a final velocity v. Work – kinetic energy theorem. In order to change the kinetic energy and hence the speed of an object you must do work on the object. [KE] = J = Nm = kg m 2 /s 2 Energy and work have the same units. PowerEfficiency e m – Mechanical Efficiency e e – Electrical Efficiency e t – Thermal Efficiency