Relate Cause and Effect What has a greater effect on
an object's kinetic energy-
doubling its mass or doubling its
speed? Explain.
Calculating Kinetic Energy You can use the following
equation to solve for the kinetic energy of an object.
Kinetic energy = { x Mass x Speed?
For example, suppose a boy is pulling a 10-kg wagon at a
speed of 1 m/s.
Kinetic energy of wagon = { x 10 kg x (1 m/s)2
= 5 kg. m?/s2 = 5 joules
Note that 1 kg. m/s2 = 1 joule
Do changes in speed and mass have the same effect on the
kinetic energy of the wagon? No-changing the speed of the
wagon will have a greater effect on its kinetic energy than
changing its mass by the same factor. This is because speed is
squared in the kinetic energy equation. For example, doubling
the mass of the wagon will double its kinetic energy. Doubling
the speed of the wagon will quadruple its kinetic energy.