A park merry-go-round consists of a 210 kg circular wooden platform 3.90 m in diameter. Four children running alongside push tangentially along the platform's circumference until, starting from rest, the merry-go-round reaches a steady speed of one complete revolution every 2.8 s.
(a) If each child exerts a force of 26 N, how far does each child run? meters
(b) What is the angular acceleration of the merry-go-round? rad/s2
(c) How much work does each child do?  J
(d) What is the kinetic energy of the merry-go-round?