【简答题】He lost his arms in an accident that caused the death of his father. Then his 36 became his shadow, never leaving him alone for years. 37 writing with his toes, he was completely unable to do anything...
【单选题】A figure skater on ice with arms extended, spins at a rate of 2.5 rev/s. After he draws his arms in, he spins at 6.0 rev/s. By what factor does the skater's kinetic energy change when he draws his arm...