Sure. There might be some confusing parts, but I tried to make it as clear as possible:
This is the code for the player's paddle, which is on the left side of the screen, drag is enabled in vertical direction.
The ball's initial angle is zero (in a horizontal direction).
I decided to use 'Bounce of solid' for the border of the layout and to use 'On collision' for the paddles.
The first two events are used to calculate the drag velocity, as described by brunopalermo.
On collision, I use trigonometry to split the ball's total speed into Ball_Velocity_X (the speed in x direction) and Ball_Velocity_Y (the speed in y direction). Then I add Drag_Velocity of the paddle to Ball_Velocity_Y of the ball and use trigonometry again to calculate the new angle of motion of the ball. That way, the velocity of the paddle affects the ball's trajectory.
Here comes the confusing thing: C2 defines a bullet's angle of motion in the range from 0 to 180 (lower half circle, clockwise speaking) and -180 to 0 (upper half circle, clockwise speaking). That means you have to use different trigonometric functions depending on whether the angle is positive or negative. If you want to program the opponents paddle, theses dependencies change!
For the opponents AI you can vary the time span in which the paddle moves towards the ball's Y coordinate.
Little bonus detail 1:
I figured out that it is very annoying when the ball is dodging almost vertically, so I decided to limit the angle to 65 (or rather -65) degrees.
Little bonus detail 2:
I think it is more interesting if the ball gains some speed at every collision, that way longer rallies get more intense.
Hope that helps!