A light object, like a tennis ball, on the edge of the trampoline will follow a curved path toward the bowling ball - like a planet orbiting the sun.

而蹦床边缘的轻物体，比如网球，将沿着曲面移向保龄球-就像行星围绕着太阳运行。

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Researchers say walking, climbing steps, biking and even dancing all count, but activities such as bowling and light housekeeping do not.

CNN: Study: Exercise cuts stroke risk by almost half

While having a strong bowling attack, their side looks very light in batting with the debutants Umar Amin and Azhar Ali coming in at three and four.

BBC: Australia pegged back by Pakistan in Lord's Test

Mohammad Aamer also took three wickets in conditions ideally suited to seam bowling, with Mike Hussey 39 not out when bad light brought an early finish.

BBC: Australia pegged back by Pakistan in Lord's Test