# Centripetal force question

1. Mar 6, 2006

### Havoc2020

We recently did an experiment in lab on centripetal acceleration. We used a spring mass mechanism and used the data we collected to compute the centripetal force. We then had to hang the spring mechanism on a stand then add weight to stretch the spring to the same index point and calculate the static force required.

So my question is why is the centripetal force required higher than the static force to stretch the spring the same distance?

Any help will be appreciated as this was not discussed in lab and we have just started the chapter on circular motion.

Thanks

2. Mar 6, 2006

### xman

think of the forces involved. try drawing a force diagram for both cases, i.e. for in motion and the static case. can you see why the in motion case would require a stronger magnitude force?

3. Mar 6, 2006

### Havoc2020

OK I drew the force diagrams and my assumption is that the force is greater for centripetal because the velocity is perpendicular to the acceleration whereas in the static force the velocity and acceleration are in the same direction.

4. Mar 6, 2006

### xman

awesome, that's right.

5. Mar 6, 2006

### Havoc2020

Thanks for the help. Drawing the force diagrams made it pretty clear.

6. Mar 6, 2006

### xman

for mechanics problems, it's the best advice i can give. usually with a good picture, any problem may be solved. awesome work.