# Vectors (with reference to a pendulum)

Why is the acceleration of a pendulum non-zero at its lowest point?

• Exactly. I just want to add this to the explanation: if $\vec{a}$ were 0, then the rod wouldn't keep moving as a pendulum, but as an straight line, because any movement without acceleration is in straight line. If it is not a straight line it's because of that centripetal aceleration. – FGSUZ Feb 21 at 21:57