The diameter of the outlet pipe of a water pump is 1dm, and the water velocity at the mouth of the pipe is 2m per second, how much water can be pumped in m in 1 minute**3.
一种抽水机出水管的直径是1dm，管口的水流速度是每秒2m，1分钟能抽水多少m**3．
<gadget id="calculator">1 / 10 / 2</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/20) ** 2</gadget>
<output>1/400 = around 0.0025</output>

<gadget id="calculator">3.14 * (1/400) * 2 * 1 * 60</gadget>
<output>0.942</output>

<result>0.942</result>