At which point or points does the pendulum have the greatest kinetic energy?

At the bottom.

Explanation:

A pendulum possess two types of energies i.e. kinetic energy and potential energy. We know that a pendulum oscillates about its mean position. At both extreme points, it have zero kinetic energy and maximum potential energy. As it swings down, its potential energy gets converted to the kinetic energy.

As a result, it have zero potential energy and maximum kinetic energy at the bottom point. Hence, the pendulum have the greatest kinetic energy at the bottom.

the duration of a photographic flash is related to an rc time constant, which is 0.100 μs for a certain camera.