Simple Harmonic Motion (easy question)

[MarineBio]

Homework Statement

A 0.26 kg mass attached to a spring undergoes simple harmonic motion with a period of 0.84 s. What is the force constant of the spring?

Homework Equations

T = 2*pi*SQRT(m/k)

The Attempt at a Solution

I know this is supposed to be an easy question, but for some reason I can't do it. Here is what I got (which is not right):

T = 2*pi*SQRT(m/k) and to solve for "k":

K = 2*pi*SQRT(m)[whole thing divided by .84 seconds] = 3.814 N/m

Ok, so what am I doing wrong? Thanks!

 

[cepheid]

Your algebra doesn't look right. To solve for k, you want to get it by itself on one side of the equation, which involves:

1. Getting rid of the 2pi (by dividing both sides of the equation by 2pi).
2. Getting rid of the square root (by squaring both sides).
3. Getting k on top (taking the reciprocal of both sides)
4. Getting rid of the m (multiplying both sides by m)

 

[nickmai123]

It might make it more clear if it looked like this:

$$T=2\pi \sqrt{\frac{m}{k}}$$

Now solve for k.

HINT: Squaring both sides gets rid of the square root.

 

[MarineBio]

ok so K = (2*pi*m)/T^2

That gives me 2.315 N/m which is also incorrect. Hmm... I don't know.

 

[Chrisas]

You forgot to square the 2*Pi

 

[MarineBio]

You forgot to square the 2*Pi

Problem solved. Thank you