Q.

A particle executes linear simple harmonic motion with an amplitude of 3 cm. When the particle is at 2 cm from the mean position, the magnitude of its velocity is equal to that of its acceleration. Then its time period in seconds is          [2017]
 

1 52π  
2 4π5  
3 2π3  
4 5π  

Ans.

(2)

Given, A=3 cm, x=2 cm

The velocity of a particle in simple harmonic motion is given as v=ωA2-x2

and magnitude of its acceleration is a=ω2x

Given |v|=|a|    ωA2-x2=ω2x

ωx=A2-x2  or  ω2x2=A2-x2

ω2=A2-x2x2=9-44=54  or  ω=52

Time period, T=2πω=2π.25=4π5 s