Pendulum question

[Eye Cue]

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Okay, so I searched for the answer and read numerous SDN threads, yet I can't find a definitive answer, just a bunch of arguing. On top of that, my study partner and I are in disagreement of the answer, so we need to put an end to this once and for all!

Simply put, is there a net acceleration at the nadir of a pendulum in motion?

I don't think there is a horizontal acceleration, however, I do think there is a centripetal acceleration pointing directly up which probably comes from the tension.

 

[Isoprop]

that acceleration is canceled by gravity. there is no net force on the pendulum at equilibrium. this is why if there is no initial displacement, a pendulum at equilibrium will not start accelerating.

 

[Isoprop]

Sorry, let me retract that b/c I slightly misread your question. If the pendulum is already in motion, then at the equilibrium point, you will observe a net instantaneous acceleration. This is because the tension of the string is not the same as the force of gravity and you have a net acceleration in the direction of the string.

 

[DendWrite]

I agree. Wikipedia has a nice animation to visualize this.

 

[Insulinshock]

As a rule of thumb objects that undergo a change in direction are experiencing an accelaration.

 

[Eye Cue]

Very helpful replies to all of you, thanks!

However, would it be correct to say that, even though it does accelerate at the bottom, the acceleration is at a minimum?

 

[loveoforganic]

I think so, because the acceleration due to tension and the acceleration due to gravity would be in opposite directions.