How to Use Physics to Escape an Ice Bowl

I don’t know who invented this crazy challenge, but the idea is to put someone in a carved-out ice bowl and see if they can get out. The bowl is shaped like the inside of a sphere, with sides that get steeper the higher you go. If you think an icy sidewalk is slippery, try going uphill on one!

To solve this problem, you can build a physics model. First, you need to understand how people walk on flat ground. When you walk, you push off with your back foot, using your muscles to apply a backward force on the Earth. According to Newton’s third law, this causes the Earth to push forward on you. That forward force is what we call friction.

The amount of friction depends on two things: the materials in contact and how hard they are pushed together. The first is captured by a coefficient, a number usually between 0 and 1. Lower numbers mean more slipperiness. The second is called the normal force, which prevents you from falling through the floor. On flat ground, the normal force from the floor is equal to your weight pushing down.

There are two types of friction coefficients: static and kinetic. Static friction determines when something will start moving, while kinetic friction determines how quickly something slows down once it’s moving. Usually, kinetic friction is a little lower than static friction. This is why it’s easier to keep an object moving than to start it moving in the first place!

Now you can use these concepts to figure out how to escape an icy bowl. You’ll need to understand how to apply these friction forces when you’re on a slippery slope instead of flat ground. There are actually three possible escape plans, and the next part will show how they work using animations.