# Frequency of the oscillation

1. Jun 6, 2009

### brunettegurl

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

A spring is hung from the ceiling. When a block is attached to its end, it streches 19.3 cm before reaching its new equilibrim length. The block is then pulled down slightly and released. What is the frequency of the oscillation?

2. Relevant equations
f =$$\frac{\omega}{2\pi}$$

$$\omega$$= $$\sqrt{\frac{k}{m}}$$

3. The attempt at a solution
i have no idea how to start this question and what to make of the mention of the equilibrium length pls. help

2. Jun 6, 2009

### Cyosis

Which two opposite and equal forces act upon the mass when the spring is in its equilibrium position?

3. Jun 6, 2009

### brunettegurl

the weight and the normal force but they dont mention any mass in the question

4. Jun 6, 2009

### Cyosis

You don't want to calculate the mass you want to calculate k/m. The restoring force exerted by the spring is equal to the weight. Can you write this down in formulaic form?

5. Jun 6, 2009

### brunettegurl

wld it be .5*k*x^2= mg where K/m = 2g/x^2 ??

6. Jun 6, 2009

### Cyosis

That is not Hooke's law. You used the elastic potential energy as a force which is not true because it is an energy. Find the correct expression for the restoring force exerted by the spring.

7. Jun 6, 2009

### brunettegurl

oh do u mean F=kx so that wld be kx=mg where k/m = g/x

8. Jun 6, 2009

Yep.

9. Jun 6, 2009

### brunettegurl

thanx i get it now :)