If you are talking about applying physics to the ball, then you need to think deeper about how Sprite Kit deals with physics.
When you specify the 'moveTo' action, you're not actually using Sprite kit's physics engine at all. You're simply specifying a point to animate that sprite to.
What you should be doing to achieve the effect you're looking for is attaching the sprite's position to your finger as it's moved around on the screen like so:
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
sprite.position = [[touches anyObject] locationInNode:self];
}
Then when the finger is lifted, you need to calculate the direction and speed in which your finger just moved and apply the appropriate amount of force
to the sprite's physics body using the applyForce
method:
[sprite.physicsBody applyForce:calculatedForce];
You will need to figure out how to calculate the force to be applied, but play around with the applyForce method and look at what information you are able to get back from the touchedMoved: event to help you apply that force. Hope that helps.