Example: A body of mass 0.5 kg travels in a straight line with velocity v = a x 3 / 2 where a = 5 m – 1 / 2 s – 1. What is the work done by the net force during its displacement from x = 0 to x = 2 m
Solution: We know that WD = Kf- Ki, now we can put value of x = 0 in the equation v = a x 3 / 2 to find initial velocity, vi = 0, Ki = 0, Similarly find vf by putting x = 2, and Kf = ½ mv 2.
Potential energy
o
Potential energy is the‘ stored energy’ by virtue of the position or configuration of a body. o
Physically, the notion of potential energy is applicable only to the class of forces where work done against the force gets‘ stored up’ as energy.
o Mathematically, the potential energy V( x) is defined, if the force F( x)
can be written as o
This relation is valid only for Conservative Forces