Q: For a particle executing SHM the displacement x is given by x = A cos ωt. Identify the graph which represents the variation of potential energy (PE) as a function of time t and displacement x

(a)I , III

(b)II , IV

(c)II , III

(d)I , IV

Ans: (a)

Sol: Potential Energy is minimum (in this case 0)at mean position (x=0) and maximum at extreme position (x= ± A)

At time t= 0 , x = A , P.E should be minimum , hence graph (I) is correct . Now in graph (III) P.E is minimum at x=0 , this is also correct .