"Why do racing cyclists crouch low over their handlebars to go faster? Why do you fall back down when you bounce on a trampoline? And why does the refrigerator door close as if it's being pulled by something invisible? The answer is forces. Gravity, friction, gears, pulleys, levers, and magnets are all explored in this title. Learn how trainee astronauts experience "zero gravity" on the aircraft known as the "vomit comet," how air resistance protected the Curiosity rover during its landing on Mars, why magnets are used at recycling plants, and how trains powered by magnets may one day travel at thousands of miles per hour!"--