Well, I have done one, maybe it was my first Construct game, using physics. Other than occasional glitches when the ball would go flying up like a bullet, it worked fine. Fixed that glitch too.
Sounds like you have it right. You have to apply impulse when it is touched. UP in Construct is -90 degrees, so apply impulse at -90 angle to make it go straight up. Then adjust so the angle is less or more depending where the ball is touched, that way if it is tuched on the right side it will bounce up and left, and the other way around. So formula would be: apply impulse at angle -90+(Ball.X-Mouse.X ( or Touch.X)) / 10
I divide by 10 because the angle can be too far from -90 if you touch too far to the left or right.
or you can use apply physics impulse toward position:
For X position set it: Ball.X+(Ball.X-Mouse.X)*2 at image point 0
For Y position just 0, which is straight up