Study of interaction between matter and energy using mechianical description
Minimum velocity occurs at the top of the trajectory, where
the projectile stops rising and starts falling. For a split second,
it has no vertical speed at all, and its velocity is only the horizontal
speed (which doesn't change).
Answer:
The angular frequencies of all the 3 pendulums shall be same.
Explanation:
The time period of a simple pendulum with the approximation
is given by:

The angular frequency
is given by

As we can see that the angular frequency is independent on the initial angle (valid strictly for small angle approximations) we conclude that the angular frequencies of the 3 pendulums are the same.
Kinetic energy is energy of motion. If the object is sitting still, then it has no kinetic energy. It doesn't matter what its mass is, or how high the shelf is.
KE = 0