yes
watch the last trick in this video
(Link moved below.)
gravity
gravity
Don't Let the Bastards Grind You Down was created in 1997.
Yes, bikes are safer than a skateboard because you can fall down when you do a flip over and you have to keep balance on a skateboard but you can hold on the handles and sit down on a bike.
Lying down.
I assume you are referring to inline skating. Yes you can grind without a grind plate. The plate is used to slow down the wear of your skate frame.
"Lying down" in French is spelled as "allongé".
Won't Take It Lying Down was created in 2000.
Prone means lying horizontal with the face down. Pronation is the action of lying prone.
"Porridge" (1974) "Saturday Night and Sunday Morning" (1960)
The friction between the foot and the ground creates a force that opposes the motion of the skateboard, causing it to slow down. This friction converts the kinetic energy of the skateboard into thermal energy.
It looks like someone lying down, either fully down or leaning back/reclining. You could be lying on your side or on your back or sitting in a reclining position like in an easy chair. Ever see anyone riding a recumbent bicycle? See the links below for demonstrative pictures.