Finding Vmax of a Block in SHM: Mass, Spring Constant, and Distance

[Litdaze]

Homework Statement

A block with mass m=200g is attached to a spring with a elastic constant of k=5.0 N/m.
The block is pushed at a distance x=5.00cm of its equilibrium position, in a surface with no friction.
Then its dropped of that position. Assume for t=0s that the block is at rest.
What is the maximum velocity of the block?

This is a multiple choice question, solutions being
a) 0.250 m/s
b) 1.25 m/s
c) 0.05 m/s
d) 5.0 m/s

Homework Equations

N/A

The Attempt at a Solution

I can't figure how to find Vmax[/B]

 

[lightgrav]

ok, that is Time Period and/or angular frequency ... do you want to use Hooke's Law (PE into KE), or do you want to use oscillation formulas?

 

[Litdaze]

Oscillations I guess, I really can't figure out how to find Vmax. I've tried the Vmax=Aw but somehow it resulted in 1, which isn't the answer.

Vmax = Aw = (0.2 kg)(5 rad/s) = 1.

I'm really confused

 

[lightgrav]

in oscillations, capital A is the oscillation Amplitude (not the mass)
You need to keep track of your UNITS !

 

[Litdaze]

Ok then so Vmax = Aw = (0.05)(5) = 0.250 m/s?

It makes sense now.

 

[Anshuman Shaw]

I think you can simply use the work energy theorem here.