The inner diameter of the water pipe is 2 cm and the velocity of water in the pipe is 8 cm per second. A classmate went to wash his hands and forgot to turn off the tap when he left. How many liters of water was wasted in 5 minutes?
自来水管的内直径是2厘米，水管内水的流速是每秒8厘米．一位同学去洗手，走时忘记关掉水龙头，5分钟浪费多少升水．
<result>7.536</result>