Momentum of a Pendulum: Angular and Linear Changes

[Timothy Schablin]

If a pendulum swings in a given arc, because of gravity acting on it in the vertical direction, does the linear and angular momentums change since it is picking up velocity because of gravity?

 

[person123]

Momentum is a vector. The magnitude of momentum changes because the velocity changes (linear and angular) and the direction of momentum also changes.

 

[Chandra Prayaga]

You can calculate what you are curious about. Use conservation of mechanical energy to calculate the speed at various points in the arc. Since the direction of the velocity is always tangential to the path, you now know the velocity at any point. Then you know the momentum. Now use the definition of angular momentum to find that. Certainly, you will find that both linear and angular momenta change as the pendulum swings.