Finding period and amplitude of a driven spring-mass system

[Husker70]

Homework Statement

A 2.00 kg object attached to a spring moves without friction and is driven
by an external force F=(3.00N) sin(2pie t). Assuming that the force
constant of the spring is 20.0 N/m determine (a) the period and
(b) the amplitude of the motion.

Homework Equations

T = 2pi sqrrt(m/k)
A = (Fo/m)/sqrrt (w^2 - wsubO)^2

The Attempt at a Solution

T = 1.99s
A = ?

I don't think that either equation is right. The answers are in
the book but these aren't working.
Thanks,
Kevin

 

[Redbelly98]

There are 2 periods, or frequencies, of relevance here: the natural frequency, and the driving-force frequency.

If your calculated period is wrong, perhaps you need to think about the other period that is relevant.