Oscillations of a Pendulum: How Many Complete by Noon and What is the Amplitude?

[kerbyjonsonjr]

Homework Statement

In a science museum, a brass pendulum bob swings at the end of a 15m long wire. The pendulum is started at exactly 8:00 a.m. every morning by pulling it 1.5m to the side and releasing it. Because of its compact shape and smooth surface, the pendulum's damping constant is only .010 kg/s.

At exactly 12:00 noon, how many oscillations will the pendulum have completed?

And what is its amplitude?

Homework Equations

w=2$$\pi$$f
w=$$\sqrt{}k/m$$
T=1/f

The Attempt at a Solution

I used w=$$\sqrt{}k/m$$ so I had w=$$\sqrt{}.01/110$$= .009 then I plugged that into w=2pif so .009=2pif f=.0015 and found the period by doing 1/.0015 and got 659 seconds. Then I converted the 4 hours minutes and got 14,400 and then I divided 14,400/659 and got 21.85.

For the amplitude I am not sure exactly how I would get that but would it just be the length of the wire or how high it goes or something else? Any help would be great. Thanks!

 

[Undoubtedly0]

Greetings! It looks like you confused k for b. Remember, in a simple pendulum,

$$\omega = \sqrt{\frac{g}{L}}$$,

although you will still have to factor in the damping constant.