(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Since I ran out of time in class, I have to make up my own times for this lab using calculations.

The lab consists of our providing a little force by shaking this tube. Inside this tube is a string, and at one end of the string is attached a hanging mass, the other end a rubber stopper. Essentially, the hanging mass's weight is what provides the centripetal force of the rubber stopper.

However, my calculations for the time in seconds are waaay too high. I tried doing the same method for my other trials done in class and they were also far too high. I don't know what I'm doing wrong, because human error couldn't have possibly been that high all 10 trials in class.

m_{1}= 0.011 kg

m_{2}= 0.030 kg

r = 0.545 m

g = 9.81 m/s^{2}

2. Relevant equations

d = r * 2 pi * 20 (we measured the time it took for 20 revolutions)

t = d / v

W = mg

F_{c}= (mv^{2}) / r

3. The attempt at a solution

Since the force we provide with our arms shouldn't factor in too much, I did:

(m_{2}v^{2}) / r = m_{1}g

v = 1.400 m/s

t = d / v

t = (2pi * 0.545 * 20) / 1.4

t = 48.915 s,

which varies WAY too much with the other trials (Each trial, a variable was altered a bit, such as the hanging mass or the radius, but this change only affected the time by 3 seconds or less).

The other trials were in the 12.0 - 15.0 s range.

What am I doing wrong?

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# Homework Help: Centripetal force lab

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