Forces & Motion A force is a push or pull on something. If a skater goes down off a ramp, what forces are acting on the board? Friction happens when objects rub against each other such as wheels and the ramp. Gravity happens to any object on Earth. Gravity pushes down on a person & the board.
Wheel is the mechanical principle at the core of transportation. The invention of the wheel has become a cultural trope, but did it actually have an inventor? The invention of the wheel has long been discussed as a crowning achievement of early mankind, but who actually invented it? By Trevor English.