Q 11-13-105JEE MainJEE Main 2021 (31 Aug, Shift 2)Easy
For a body executing S.H.M.:
(a) Potential energy is always equal to its K.E.
(b) Average potential and kinetic energy over any given time interval are always equal.
(c) Sum of the kinetic and potential energy at any point of time is constant.
(d) Average K.E. in one time period is equal to average potential energy in one time period.
Choose the most appropriate option from the options given below:
Answer: (A) (c) and (d)
(a) False: K.E. and P.E. are equal only at $x = \pm\dfrac{A}{\sqrt2}$.
(b) False: the averages are equal over a full period (or half period), not over any interval.
(c) True: total mechanical energy is conserved.
(d) True: each averages to $\dfrac14kA^2$ over a period.
Solution by Sreeraj P, M.Sc Physics