# Homework Help: Spring constant of a thread

1. May 27, 2009

### brunettegurl

1. The problem statement, all variables and given/known data

A 2.60 g spider is dangling at the end of a silk thread. You can make the spider bounce up and down on the thread by tapping lightly on his feet with a pencil. You soon discover that you can give the spider the largest amplitude on his little bungee cord if you tap exactly once every 4.90 s seconds. What is the spring constant of the silk thread.

2. Relevant equations

$$\omega$$= 2$$\pi$$/T
$$\omega$$= $$\sqrt{}k/m$$

3. The attempt at a solution
so i equated the 2 equations and tried to isolate for k and this is what my equation looked like : m*(2$$\pi$$/T)^2 = k ..i tried rearranging twice and my answer and equation are coming out the same ..pls. help

2. May 27, 2009

### Staff: Mentor

That looks fine to me. Why do you think it's not?

3. May 27, 2009

### brunettegurl

when i put the answer into my hwk the answer is appparently wrong..i was also wondering if i was right in assuming the period to be 4.90 seconds??

4. May 27, 2009

### nrqed

What value did you get ? Did you convert the mass to kg ? (I assume they want the k in N/m)

5. May 27, 2009

### brunettegurl

the value i am getting is 4.85x10^-3 N/m

6. May 27, 2009

### Staff: Mentor

Yes, that was correct.

7. May 27, 2009