Transcript: Bumper Car Science

Now, not all theme park rides rely on stomach churning thrills, but they do all involve science.

Take bumper cars. Now, what sort of science could possibly be behind bumper cars? Well, here to explain it all is physicist Nathan Langford.

Thanks, Rob. So, to explain the science of bumper cars … You right, Rob?

Thought maybe I could … help?

All right, let’s go.

So, to explain the science of bumper cars we need the following things: we need the Laws of Physics, according to Sir Isaac Newton, we need some bumper cars, we also need some guinea pigs.

Newton’s First Law of Motion says that an object at rest will stay at rest until acted on by a force.

This is also called the Law of Inertia. Inertia means resistance to change, so this applies to objects that are moving, too. They’ll continue moving at the same rate until acted on by an external force.

This explains why Dr Rob’s body keeps moving, even though his car stops suddenly. Let’s take a closer look.

The wall exerts a force on Dr Rob’s car, so it stops. But there’s no force on his body, so it keeps moving. And that’s why seatbelts are so important.

But how much force do we feel in a collision? Well, Newton worked that out too, using momentum.

Momentum is equal to mass times velocity. In this case the mass is Damien plus the car, and that doesn’t change. The velocity is how fast he’s travelling in a particular direction. And that we can change.

The faster he goes, the more momentum he has. The more momentum he has, the greater the force that Dr Rob will feel in the collision. That’s because momentum isn’t lost in a collision but is conserved. So whatever momentum Damien has is transferred to Dr Rob.

So that explains what happens to Dr Rob. But what about Damien? Why does he feel a force too?

Well, you guessed it. That’s another of Newton’s laws, that every action has an equal and opposite reaction. So whatever force Damien applies to Dr Rob comes back to him in the opposite direction. This explains why Damien stops when he bumps into Rob, even though he hit Rob.

Something else that shows action and reaction is Newton’s cradle. So this time we need three cars.

I collide with Dr Rob, who then collides with Damien. Both of these cars also push back, so Damien feels the full force of the collision and Dr Rob stays still.

But it doesn’t end there. Bumper cars have rubber bumpers, so they bounce. Normal cars are made to crumple in a collision, instead of bouncing back. This absorbs some of the force and helps to protect the people in the car.

Well, that’s about it for bumper car science. You had enough, Rob?

I’ve had enough. Here’s some theme park science you can try at home.