Simple ball and club interaction based on the clubs normal

Question

I am playing with creating a mini-golf game and would like to apply the basic forces of the club and ball.

The problem I am struggling with is when the club (assume its a perfect square face) collides with the ball. I know the ball's mass, the contact time of the club and the change in velocity of the ball. With that I think I can get the impulse force to apply to the ball.

What I cannot figure out is the direction of the force. I thought it might be easier to understand by thinking of the ball moving and hitting the club face.

1. The angle of incidence would be the same before and after the collision. So the direction would be simple to get to.

2. If I rotate the view so the ball moves straight down, obviously the same outcome can be expected.

3. Now if I keep the ball still, but move the club towards the ball it should it not yield the same results ? The ball would move right in the 3rd image?

Something with my assumption is wrong as it looks like the ball should be moving in the direction of the normal of the club.

Answer 1

it looks like the ball should be moving in the direction of the normal of the club.

That depends on the frame you are watching from. These two situations:

• In the frame with the club at rest, the ball moves to the right.
• In the frame with the club moving up, the ball moves diagonally up and right

...are completely consistent with each other. Both could represent the identical collision, just from different observers.

Now if I keep the ball still, but move the club towards the ball it should it not yield the same results ?

The club is moving differently in those two situations (one moving, one at rest). You should not expect the ball to move identically in both either.