Question

An object vibrates with an amplitude of 6cm and a frequency of 0.490Hz. Starting from maximum displacement in the positive direction, when will be the first time that its displacement is 2cm?

Answer 1

Explanation:

x=acos(wt+delta)

f=0.49hz

omega=2πf

=2×22/7×0.49=2×22×0.07

=0.308

given amplitude=6cm

x=2cm

2=6cos(wt)

wt=cos inverse of(1/3)

t=cos inverse of 1/3/w( w nothing but omega substitute from above)