echoyjeff222

5+ Year Member
Jun 17, 2013
362
52
Status
Medical Student (Accepted)
I'm struggling to understand this question.... the setup is a basic pendulum. I understand how they do it, but what about TBR's way of saying the restoring force is F = - mg sintheta? Can't I just set that equal to ma and solve for acceleration, giving me a = gsintheta? Is this a different acceleration? I feel like I'm simplifying something.

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Aug 25, 2011
92
3
Status
Pre-Medical
They are looking at acceleration in the x and y components.

Your method is partially correct but you only account for the x direction with ma = Fr = mgsintheta, so a (in x direction) = gsintheta