Thanks in advance.... I am trying to conceptually get my arms around backspin placed upon a golf ball when an angled(lofted) putter strikes a ball. -I'm assuming as you can see in the attachment that the two objects meet with the horizontal center of gravity at the same location so any twisting of the putter('gear effect' in golf) is eliminated. When an angled object meets a ball, my education tells me there should be some ball compression and the ball should ride up the face of the putter causing the ball to rotate(backspin). The more angle(loft) the more rotation takes place. Here is where it gets interesting. There are a lot of designs now that have grooves in the face of the putter. These grooves add to the friction of the ball and putter, hence any compression and face riding of the ball should if I am correct be greater. These groove designs are claimed to cause "overspin" vs the flat surfaced face. I disagree with this claim. Unless a golfer strikes the golf ball with a tangent vector in an upward direction that somehow supersedes the "physics" inherent in the backspin equation. At some point the upward vector strike will cause more friction than the friction seen with the ball riding the face and thus top spin could be a reality. Any thoughts on this, equations, etc. Thanks.