Simple Harmonic Motion of a body

[v_pino]

Homework Statement

A body is in simple harmonic motion of amplitude 0.50m and period 4pie seconds. What is the speed of the body when the displacement of the body is 0.30 m?

Homework Equations

Would it be x=Acos2(pie)ft ?

The Attempt at a Solution

I tried substituing in x= 0.30 and A=0.50 and f= (1/ 4pie)

The answer should be 0.20 ms^-1

 

[Leong]

if the equation you gave was for displacement, then you will need to differentiate it to find the function of velocity.