Two identical particles move along the same straight line according to and

PHYSICS · Single correct · A Level · Physics · Further mechanics and thermal physics · Further mechanics and thermal physics

Problem

Two identical particles move along the same straight line according to

\displaystyle x_1 = A\cos \omega t

and

\displaystyle x_2 = A\cos\bigl(\omega t + \dfrac{\pi}{3}\bigr)

. If

T

is the time period, the time after

t=0

when they first have the same displacement again is (a)

\dfrac{T}{6}

(b)

\dfrac{7T}{12}

(c)

\dfrac{5T}{12}

(d)

\dfrac{T}{3}