Which design will launch the roller coaster car the fastest? I need to write 5 paragraphs for this scientific argument, and it's due tomorrow, I need help ASAP.

In an experiment, how can i change human errors? be specific.

At 20∘c, the hole in an aluminum ring is 2.800 cm in diameter. you need to slip this ring over a steel shaft that has a room-temperature diameter of 2.804 cm . 1. to what common temperature should the ring and the shaft be heated so that the ring will just fit onto the shaft? coefficients of linear thermal expansion of steel and aluminum are 12×10−6 k−1 and23×10−6 k−1 respectively.

Acar is traveling 35 mph on a smooth surface . if a balanced force is applied to the car what happens?