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

While waiting for your plane to take off, you suspend your keys from a thread and set the resulting pendulum oscillating. It completes exactly 90 cycles in 1 minute. You repeat the experiment as the plane accelerates down the runway, and now find the pendulum completes exactly 97 cycles in 1 minute.

Find the plane's acceleration.

2. Relevant equations

T = 2 pi sqrt(L/g)

T = 1 / freq.

3. The attempt at a solution

T_{1}= 2 pi sqrt(L/g)

(T_{1}/ (2 pi))^{2}g = L

T_{2}= 2 pi sqrt(L/(g + a))

a = L / (T_{2}/ (2 pi))^{2}- g

a = (T_{1}/ (2 pi))^{2}g / (T_{2}/ (2 pi))^{2}- g

I get that a = 1.58, but that's wrong. The right answer is 5.8. What did I do incorrectly?

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# Homework Help: Pendulum Keys Physics Question

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