Oscillating in Simple Harmonic Motion?

[jisrael93]

Homework Statement

A 200-g object is oscillating in simple harmonic monition with an amplitude of 2 cm and a period of 0.4 seconds. Find the velocity when its displacement from the equilibrium position is 0.5 cm.

Homework Equations

Restoring Force = -(constant force)(displacement)
Elastic PE = 1/2 k(s squared)
velocity = $\sqrt{k/m(A squared - s squared}$

The Attempt at a Solution

I just need help finding the constant force. If I can figure out how to solve that variable, I can finish the problem just fine.

 

[gneill]

Homework Statement

A 200-g object is oscillating in simple harmonic monition with an amplitude of 2 cm and a period of 0.4 seconds. Find the velocity when its displacement from the equilibrium position is 0.5 cm.

Homework Equations

Restoring Force = -(constant force)(displacement)
Elastic PE = 1/2 k(s squared)
velocity = $\sqrt{k/m(A squared - s squared}$

The Attempt at a Solution

I just need help finding the constant force. If I can figure out how to solve that variable, I can finish the problem just fine.

I think you mean the "force constant", k, for the spring. Why not consider the formula for the period of a mass-spring system?

Also try using the x² and x₂ icons in the edit frame header to produce superscripts and subscripts

 

[azizlwl]

Also try using the x² and x₂ icons in the edit frame header to produce superscripts and subscripts

I missed them too.
Hope they are repositioned at Quick Symbols and adding new symbol, 1/2.

Thank you.

 

[jisrael93]

I think you mean the "force constant", k, for the spring. Why not consider the formula for the period of a mass-spring system?

Also try using the x² and x₂ icons in the edit frame header to produce superscripts and subscripts

Thanks, I'm not sure how I missed that - I think the first part of this homework fried my brain before I got to this and I just forgot to look at my other equations! However, when I acquired a k value of 49.35 and did the equation in my original post for velocity, I acquired a negative number under the radical, therefore giving me a non-real answer. Am I doing something wrong?

 

[gneill]

Thanks, I'm not sure how I missed that - I think the first part of this homework fried my brain before I got to this and I just forgot to look at my other equations! However, when I acquired a k value of 49.35 and did the equation in my original post for velocity, I acquired a negative number under the radical, therefore giving me a non-real answer. Am I doing something wrong?

Your value for k looks fine (you should include units when you present a number).

The equation you wrote for velocity is okay. Maybe finger problems on the calculator?
Why not show your calculation step by step?