Question

A particle of mass m starts from the mean position of a SHM, at t=0, and goes towards -A. If the angular frequency of SHM is w, find the force acting on it as a function of time.

(a) mAw^2sin(wt)

(b) mAw^2sin(wt+π)

(c) -mAw^2cos(wt+π)

(d) -mAw^2cos(wt)

I had been asked this question during an online exam.

This key question is from Oscillations topic in section Oscillations of Physics – Class 11

Answer 1

Right option is (a) mAw^2sin(wt)

The explanation is: The displacement equation will be given by: x = -Asin(wt).                                                                        On taking its derivative, we get:                                                                                                                                           v = -Awcos(wt).                                                                                                                                                        Further, we get: a = Aw^2sin(wt).                                                                                                                                       Thus, force is given by: F(t) = mAw^2sin(wt).