Rollercoasters: Potential vs. Kinetic Energy

Rollercoasters (mostly) don’t have engines. Once the chain lift drags the train to the top of the first hill (“The Lift Hill”), the motor turns off. The rest of the 2-minute ride—the loops, the corkscrews, the turns—is powered purely by Gravity.

The Energy Bank Account

Physics is a bank.

• Height = Potential Energy (PE): $$PE = mgh$$ (Mass × Gravity × Height).
  • At the top of the hill, your account is full of PE. Speed is 0.
• Speed = Kinetic Energy (KE): $$KE = 1/2 mv^2$$.
  • As you drop, PE turns into KE. You lose height, you gain speed.
• The Rule: You can never go higher than your starting hill. Friction (the Taxman) steals energy throughout the ride (Heat and Sound), so every subsequent hill must be smaller.

Robotics Application: Gravity Assist

We use this Passive Energy to save battery.

• The Deployment: We fit our robots into an 18-inch box. To expand, we don’t always use motors.
• The Spring and Gravity: We might release a latch. A spring pushes an arm past the “tipping point,” and then gravity slams it into place.
• Droppers: When scoring game pieces into a low goal, we just open a door and let gravity do the work. It’s faster and more reliable than a specialized “pusher” arm.

The Loop-de-Loop (Centripetal Force)

Why don’t you fall out of a loop? Centripetal Force. Your body wants to go straight (Newtons 1st Law). The track forces you to curve. This creates a “G-Force” that pins you into your seat.

• Robotics: When our flywheel shooter spins a ball, the ball is pinned against the outer wall of the shooter by this same force. We use this friction to imbue the ball with spin (Backspin) for a stable flight path.

Conclusion

A rollercoaster is a machine designed to be inefficient (it turns height into screams). A robot is designed to be efficient. But we still obey the same laws. We “bank” energy in flywheels and springs, and we “spend” it to score points.