Eli5 How do rollercoasters work?



What keeps rollercoasters at a continuous speed throughout the ride so that it’s able to complete twists, turns and loops?

In: Engineering

Rollercoasters actually don’t keep a consistent speed. They get towed up to the top of the first hill, then that potential gravitational energy is all the energy they will ever have. From there, the car is simply rolling down the hills. They have enough energy to roll up another smaller hill then back down again, but that’s just left over momentum from the first drop. Nothing ever adds energy after the first towing up the first hill. It’s all just controlled falling

Gravity, momentum and motors.

Many rollercoasters have motors either on the track or the coaster itself that pull it up hill. Then gravity pulls it back down. It doesn’t go at a continuous speed, there will be slower and faster sections.

It’s not much different then riding a bike up and down hills. You use a lot of effort to get to the top of the hill, then coast and pick up speed going down hill. Once you’ve got all that speed built up, you can go up a smaller hill without pedaling, trading your speed for elevation and getting slower as you move up.

For turns and loops it’s the same thing, just building up enough speed that your momentum will carry you through the loop. Rollercoasters are carefully designed for how fast they should be going on any part of the track to ensure they’ll have enough speed to do loops, but not so much speed that they become too dangerous.

In a nutshell, momentum.

Everything on a coaster, all its twists, turns and weight, have been calculated to be able to get past the opposing forces through momentum alone.

This is why there’s a lift hill as the first thing on most coaster setups.

Of course, there are things like acceleration on tracks that help propel the coaster forward that uses things like wheels or even electromagnets.

Here is a very good youtube channel, Amusement Labs, that actually teaches the tech behind these things.