Steel bars placed inside concrete to keep heavy structures from cracking under tension
Option Two
A type of lightweight recycled plastic beam used to construct train tracks
Option Three
An electronic sensor installed on bridges to measure vibrations
What is rebar?
Drop Answer
10%
Option Three
67%
Option Two
98%
What percentage of modern construction rebar comes from recycled scrap metal like old cars and appliances?
Drop Answer
Option Three
Radio sensors along the track talk constantly to onboard computers
Track workers flip manual levers as trains pass
Option Two
Satellite cameras watch the tracks from outer space
How does the control center track the exact location of every train down to the centimeter?
Drop Answer
It turns into waste heat on the brake pads.
Option Two
It is converted into light for station lamps.
Option Three
"Regenerative braking" turns the motor into a generator, sending electricity back into the power grid.
When an electric train slows down as it enters a station, where does all that kinetic energy go?
Drop Answer
By riding high-altitude wind currents
Option Two
By flying lower to the ground where air is thicker
Option Three
By turning off the engines during mid-flight cruise
How do pilots flying long distances save fuel during their flight?
Drop Answer