Other forces used iin skateboarding
friction
gravity
motion
acceleration
The grind is when one or both of the trucks , make contact and grind along a ledge, coping, or rail.
The rider does an ollie high enough so he/she can land on the surface to grind.
When the rider is locked in to the grind .
He/she has to overcome friction, which slows the rider down.
Some surfaces create more friction than that of others.
Grinding a slick metal box will have a lot less friction than an old piece of wood, therefore sliding better.
Waxing a curb or piece of wood grealty increases the rate of momentum that can be gathered and therefore overcomes friction with a bit more ease
Once the rider has overcome the first bit of friction, and is now grinding ,it gets easier.
Once locked on , he/she has momentum.
Newton's law declares that now, the body wants to keep going forward and grinding.
To get out of the grind, the rider simply pushes down with the back foot and turns, and absorbs the impact upon landing.
Or you can Ollie out and the more advanced skatboarder can kickflip out