# SOS: Pendulum and Spring Problems

1. Feb 21, 2006

### hydrophobicmermaid

I would be SOOO grateful if anyone could tell me how to accomplish these problems. My teacher has never gone over any of this, though I might be making it more complicated than need-be...

1) A pendulum has a mass of 2.6 kg, a length of 2.3 meters, and swings through a (half)arc of 16.8 degrees. What is its amplitude to the nearest centimeter?

2) To the nearest tenth of a Joule, what is its maximum kinetic energy of the pendulum in problem 1?

3) A mass of 2.1 kg is dropped from a height of 3.27 meters above a vertical spring anchored at its lower end to the floor. If the spring constant is 25 N/cm, how far, to the nearest tenth of a cm, is the spring compressed?

4) If the top of the spring in the preceding problem is 1.24 meters above the ground when the mass is released, what is the ball's kinetic energy, to the nearest Joule, just before the mass strikes the spring?

Thanks sooo much!
Sara

2. Feb 21, 2006

### dicerandom

What have you tried thus far?

3. Feb 22, 2006

### phucnv87

Some clue

1)$$x=R\theta$$

2), 3) and 4) Using the conservation of energy.