Work is a measure of energy transfer between a system and the adjacent regions. Potential Energy (PE) and Kinetic Energy (KE) of an object increases when positive work is done on it when there is no friction present. Work is done when the force exerted on the object causes a displacement in a particular direction. If the force is constant and parallel to the object’s path, work can be calculated using:
W=F.s
Where F is the constant force and s is the displacement of the object. If the force is not constant, we can still calculate the work using a graphical technique. If we divide the overall displacement into short segments, ∆s, the force is nearly constant during each segment. The previous expression can be used when calculating the work done in the given segment. The total work for the overall displacement is the sum of the work done over each individual segment:
W=∑ F (s) ∆s
This sum can be determined graphically as the area under the plot of force vs. position. The expressions for work can be derived from the application of Force sensors and a motion detector. In either case, the work-energy theorem relates the work done to the change in energy as:
W = ∆PE + ∆KE
Where W is the work done, ∆PE is the change in potential energy, and ∆KE the change in kinetic energy.
It can be concluded that work is done when a constant force F, is applied to an object consequently causing a displacement s. Energy is involved in doing the work and energy can neither be lost nor created, rather it is transferred from one form to another. Potential energy (PE) and Kinetic energy (KE) are the main forms of interchangeable energy. Hence work can be defined as a function of potential energy and kinetic energy.
References
Fowler, Michael. Momentum, Work and Energy. Malden: Blackwell Publishers, 1996. Print.