# Pendulum Problem!

1. Dec 2, 2006

### vinny380

The length of a simple pendulum is .760m, the pendulum bob has a mass of .365 kg, and it is released at at angle 12 degress to the vertical.
A. Find the frequency. Assume SHM.
B. What is the pendulum bob's speed when it passes through the lowest point of the swing
C. What is the tot al energy stored in this oscilation, assuming no loses.

So A is really easy:
F=(1/2pi)sqrt(9.8/.76)
F= .57

For me, B is the hardest part because I can not find a relevant formula connecting velocity with pendulums. Can anyone advise me how to do this part??

C. I havent worked on this part yet, but I am ready sure you just have to use the formula E= .5mv^2 +.5kx^2.

Thanks!

2. Dec 2, 2006

### Staff: Mentor

Consider conservation of mechanical energy.

That last term is elastic potential energy--but I don't see any springs in this problem. What other form of energy is relevant here?

3. Dec 2, 2006

Hint regarding B: conservation of energy.

Edit: too late.

4. Dec 2, 2006

### vinny380

so I should use this for B : (1/2)mv2 + (1/2)Iω2 ???????????

5. Dec 2, 2006

### Staff: Mentor

No. What two types of mechanical energy are involved as the pendulum swings?

6. Dec 2, 2006

### vinny380

Potential and Kinetic energy?

7. Dec 2, 2006

### Staff: Mentor

Yes, but what kind of potential energy?

8. Dec 2, 2006

### vinny380

mechanical potential energy ?

9. Dec 2, 2006

### Staff: Mentor

Here's a hint: What kind of energy changes as the bob rises and falls?

10. Dec 3, 2006

### crcrzy12

potential and Kinetic

11. Dec 3, 2006

### dkoppes

Gravitational potential