用一台额定功率为P0=60kW的起重机,将一质量为m=500kg的工件由地面竖直向上吊起,不计摩擦等阻力,取g=10m/s2.求:
⑴____ school chicken
⑵____ where when
⑶____ cats kites
⑷____ this thin
⑸____ kids beds