Introduction and Theory

The energy that an object has due to its motion is called kinetic energy and is defined as
K = Z In v2 (1)
where m is the object’s mass and visits speed. An object will also have gravitational potential energy
depending upon its location relative to a reference point. Near the surface of the Earth this can be
written as
U = m g y (2)
where g is the acceleration due to gravity and y is the vertical position of the object relative to an
arbitrary reference point.
Another form of potential energy is elastic energy contained in a deformed elastic object such as a
stretched (or compressed) spring. Mathematically this kind of energy can be expressed as
Usp = % kxz (3)
where k is the spring constant and X is the distance the spring is stretched.
The total mechanical energy of an object is defined as the sum of kinetic energy and any potential
energy associated with that object:
E = K + U + USp (4)
When there is no energy input or energy lost from a system its total mechanical energy will remain
constant. In everyday life this law of conservation of energy is most easily observed by transformation of
potential energy €“ either gravitational or that of a loaded spring €“ into kinetic energy of a moving body.
Likewise, a moving object can transform its kinetic energy into potential energy by climbing a slope or
stretching/compressing a spring.
Objective