PHYYYYYYY唔適啊 THXXX

tze

2011-09-06 3:42 am

the two arms of a beam balance are NOT equal in leangh :9.8 cm and 10.2cm when a block of unknown mass M kg is placed at the end of shorter arm,the reading of the mass of the block is 3kg.however his deviates from the actual mass of the block.(a) fina the value of M
唔明啊!!!!!!!!!!!個BEAM BALANCE都無WEIGHT 如何計???
THXXXXXXXXXXXXXX

更新1:

完全唔明 = = 可唔可以解釋 THXXX

更新2:

佢幾時話有另外一個BLOCK在另一條ARM道?? 佢只係話得3 kg 一個BLOCK 在短個個ARM道另外個BEAM BALANCE都無 WEIGHT 比你根本不能計算 THXXXXXX

回答 (1)

天同

2011-09-06 3:59 am

✔ 最佳答案

Just take moment about the pivot,

9.8M = 10.2 x 3
i.e. M = 10.2 x 3/9.8 kg = 3.122 kg

2011-09-05 22:44:34 補充：
The 3 kg mass balances the mass M. Hence, at equilibrium, clockwise moment about the pivot equals to the anticlockwise moment.

2011-09-06 10:16:52 補充：
Look at a diagram of a beam-balance from the following web-page

http://www.thefreedictionary.com/beam+balance

Also, pay attention to the sentence in the question: "... the reading of the mass of the block is 3kg..."

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