Author: mercuur
Subject: dwelltime
Posted: 09/18/2013 at 4:22pm
Infinite dwelltime is possible for a collission of two lumbs of clay when they stick, throwing a dart arrow to a dartboard or two magnets collide. These are all examples of a bounce but without a strong enough rebound to brake contactforces.
Throwing a piece of clay to a wall can combine plastic deformation (not elastic) with a re-bounce and two claylumbs can have a re-bounce and deform plastical with it.
Some new rubbers have a slight grainy texture to the surface that avoids a vacuumsealing effect between the ball and an all slick surface for more speed with - what they hope - little loss of spin.
spin speed ratio to avoid accelleration or decelleration to the table
depends on more then speed/spin ratio.
When speed parallel to the table is high it needs more spin to avoid friction.
It has a gravity component involved also. The ball also falls which gives a normal force between ball and table that depends on the height the ball comes from.
Spin/speed ratio adapted to height / forward ratio then ?
But things as a harder floor or softer floor or different table could also make a difference.
Maybe use angle in and angle out. When this is mirrorlike reflected the loss of kinetic momentum could also be minimal.
Subject: dwelltime
Posted: 09/18/2013 at 4:22pm
Infinite dwelltime is possible for a collission of two lumbs of clay when they stick, throwing a dart arrow to a dartboard or two magnets collide. These are all examples of a bounce but without a strong enough rebound to brake contactforces.
Throwing a piece of clay to a wall can combine plastic deformation (not elastic) with a re-bounce and two claylumbs can have a re-bounce and deform plastical with it.
Some new rubbers have a slight grainy texture to the surface that avoids a vacuumsealing effect between the ball and an all slick surface for more speed with - what they hope - little loss of spin.
spin speed ratio to avoid accelleration or decelleration to the table
depends on more then speed/spin ratio.
When speed parallel to the table is high it needs more spin to avoid friction.
It has a gravity component involved also. The ball also falls which gives a normal force between ball and table that depends on the height the ball comes from.
Spin/speed ratio adapted to height / forward ratio then ?
But things as a harder floor or softer floor or different table could also make a difference.
Maybe use angle in and angle out. When this is mirrorlike reflected the loss of kinetic momentum could also be minimal.