Condition of SHM

Acceleration is directly proportional to negative of displacement of particle

If ‘a’ is acceleration

x is displacement

Then, for Simple Harmonic Motion,

a = – kx where k is constant

**(a)** a = 0.7x

This is not in the form of a = -kx

Hence, this is not SHM

**(b)** a = – 200x^{2}

Clearly, it is not SHM

**(c)** a = -10x

This is in the form of a = -kx

Hence, this is SHM

**(d)** a = 100x^{3}

It’s clear it is not SHM

Answered by Abhisek | 1 year agoA mass attached to a spring is free to oscillate, with angular velocity ω, in a horizontal plane without friction or damping. It is pulled to a distance x_{0} and pushed towards the centre with a velocity v_{0} at time t = 0. Determine the amplitude of the resulting oscillations in terms of the parameters ω, x_{0} and v_{0}. [Hint: Start with the equation x = a cos (ωt+θ) and note that the initial velocity is negative.]

A body describes simple harmonic motion with an amplitude of 5 cm and a period of 0.2 s. Find the acceleration and velocity of the body when the displacement is

**(a)** 5 cm

**(b)** 3 cm

**(c)** 0 cm.

A circular disc of mass 10 kg is suspended by a wire attached to its centre. The wire is twisted by rotating the disc and released. The period of torsional oscillations is found to be 1.5 s. The radius of the disc is 15 cm. Determine the torsional spring constant of the wire. (Torsional spring constant α is defined by the relation J = –α θ, where J is the restoring couple and θ the angle of twist).

Show that for a particle in linear SHM the average kinetic energy over a period of oscillation equals the average potential energy over the same period.

You are riding in an automobile of mass 3000 kg. Assuming that you are examining the oscillation characteristics of its suspension system. The suspension sags 15 cm when the entire automobile is placed on it. Also, the amplitude of oscillation decreases by 50% during one complete oscillation. Estimate the values of

**(a)** the spring constant k and

**(b)** the damping constant b for the spring and shock absorber system of one wheel, assuming that each wheel supports 750 kg.