A sledge is a trailer which runs on runners rather than wheels.
Friction is actually not helpful to runners on a sledge, as it can slow down the motion of the sledge. To make the sledge move faster or smoother, reducing friction between the runners and the surface they are sliding on would be more beneficial. Lubricants or smoother surfaces can help decrease friction and improve the performance of runners on a sledge.
A sledge-dog.
Toboggan is the word you are looking for. A toboggan is a simple sledge (or sled). It has no runners or skis on the underside and is just used on snow.
a sledge
The inclined plane in the form of a ramp. A sledge with narrow runners which reduced friction. Friction was further reduced by pouring a lubricant such as water or oil under the runners. The motive force was the brute force of thousands of naked slave labourers.
Activision, infinityward and sledge hammer games
1. Call an ambulance2. Call the police and bring charges against that person.
The coefficient of friction for sledge runners on grass is much higher than on ice, so there will be a large and sudden increase in the retarding force. The deceleration will be this force divided by the total mass. If the rider doesn't hang on he/she will tend to continue at the latest velocity (ie thrown forward off the sledge).
Cheating.
Activision, infinityward and sledge hammer games
* sled * sleigh is probably the one * sledge * toboggan skibob