质量为60kg的建筑工人,不慎从高空跌下,幸好弹性安全带的保护使他悬挂起来.已知弹性安全带的缓冲时间是1.5s,安全带自然长度为5m,g取10m/s2,则安全带所受的平均冲力的大小为( )
一块长方形场地的长是60米,宽是30米,把它画在一幅1:1000地图上,长是____厘米,宽是____厘米.
—It's too hot. Would you mind _______ the door?
—_______, please do it now.