A sledge is a trailer which runs on runners rather than wheels.
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).
Yes, it is really helpful as it causes heat which burns the snow (a little) and the ski or sled actually runs on a layer of water. If there was no friction, you would not move.
Activision, infinityward and sledge hammer games
Cheating.
* sled * sleigh is probably the one * sledge * toboggan skibob