Can you help me understand a few basic things?

[binarypat]

I am working on a platformer where the player runs horizontally and the enemy (a dragon) is flying.

When the player is in range, the enemy attacks by swooping down on the player. The enemies goal is to hit the player.

In the enemy's update method, I calculate the angle and direction that the enemy should fly in to hit the player and update the angleVelocity and Velocity on the enemies body.

Here are my questions:
a) is my solution to the problem correct?
b) would it better to update the angle instead of the angleVelocity?
c) would it be better to update force instead of velocity?

I do not understand the difference between velocity and force, and when I should set one or the other?

Admittedly I mostly flying blind with respect to physics, so feel free to recommend a book, sample code, or article that will enlighten me.

TIA

-Pat