USA

A good bobsled has to take advantage of the forces that help accelerate, and has to minimize the force that slows it down. The acceleration caused by gravity is the same for all sleds in the race. But, drag, friction, and momentum all vary on the design of the bobsleigh. At the beginning to the run, the runners must run as fast as they can to push the bobsleigh down the hill. As the sled starts to go down hill, the runners dive in the sled and gravity takes control and forces it down the track. As they rocket down the course at speeds up to 130km/h, the bobsledders will experience 5G’s or five times the force of gravity.

After the push-off, gravity and momentum take over, accelerating the bobsled downhill. The driver has to choose a path down the run very, very carefully. Steering too high on a curve adds to the total distance the bob has to travel, making the trip take more time. A driver who steers too low loses the advantage of centrifugal force that keeps the bob going during banked curves. The riders also try to reduce friction on the sled. Every curve and edge of the course can slow the sled down if it rubs against the sides. If the sled loses the momentum gained during the push, the sled cannot gain that momentum back.

The weight of the bobsleds varies from sleigh to sleigh. The heavier the sled the faster it goes, but the sled and the team members’ weight must be under a weight limit. Gravity is constant for all sledders, no matter their mass or weight.

Without friction, it would be impossible for the team to move the sled. That is why everyone wears spiked shoes for better traction. Bobsledders wear skintight suits to help reduce drag on the way down the track. Bobsleighs are steered by the pilot, using two steering rings. Only small steering adjustments are necessary to guide the sled, a little bit too much either way can result in a crash. The crew also leans into curves to aid in steering the sled.