Coaster Physics

Maya stood in line for the Thunder Loop, the tallest roller coaster at the park. Her heart was pounding. "How does it even work?" she asked her big brother, Leo. "It doesn't have an engine!"

"It's all physics," Leo said with a grin. "Watch."

They climbed into the front car. Click, click, click. A chain pulled the train up the first giant hill. "That chain is a force," Leo said. "A force is just a push or a pull."

At the very top, the train stopped for a second. Maya could see the whole park! "Right now we have tons of potential energy," said Leo. "The higher we are, the more stored energy we have."

Then the train tipped over the edge. WHOOSH! Gravitational force pulled them straight down. They went faster and faster. That's acceleration! Scientists even measure gravity's pull with a letter: g. On the big drop, Maya felt pressed into her seat.

At the bottom of the hill, the train was zooming. All that stored energy had turned into kinetic energy, the energy of motion. Their speed was over 60 miles per hour! And because they were heading down and to the left, Leo said their velocity was 60 miles per hour going down-left.

Next came the loop. The train raced around in a circle, upside down! Centripetal force kept the train moving in its circle and pressed Maya into her seat so she didn't fall.

The full train had a lot of mass, because it was packed with people. Heavy and fast means lots of momentum. "That's why coasters need strong brakes," Leo said.

At the end, the brakes squeezed the train. The rubbing made friction, which slowed them down. When the train stopped, Maya's body kept leaning forward. "That's inertia!" Leo laughed. "Your body wanted to keep moving."

Maya climbed out with shaky legs and a huge smile. "Physics is awesome," she said. "I have so much energy, I want to ride again!"