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 T1 = 2 pi sqrt(L/g) (T1 / (2 pi))2 g = L T2 = 2 pi sqrt(L/(g + a)) a = L / (T2 / (2 pi))2 - g a = (T1 / (2 pi))2 g / (T2 / (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?