A balanced lever has two weights on it, the first with mass 7 kg 7kg and the second with mass 55 kg55kg. If the first weight is 9 m9m from the fulcrum, how far is the second weight from the fulcrum?

2 Answers
Apr 7, 2018

The distance is =1.15m=1.15m

Explanation:

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The mass M_1=7kgM1=7kg

The mass M_2=55kgM2=55kg

The distance a=9ma=9m

Taking moments about the fulcrum

M_1xxa=M_2xxbM1×a=M2×b

The distance is

b=(M_1xxa)/(M_2)=(7*9)/(55)=1.15mb=M1×aM2=7955=1.15m

Apr 7, 2018

Approximately 1.151.15 meters from the fulcrum

Explanation:

On a balanced lever, we have the following relationship:

m_1d_1=m_2d_2m1d1=m2d2

  • m_1,m_2m1,m2 are the masses of the two objects

  • d_1,d_2d1,d2 are the distances of the two objects from the fulcrum

And so, we got:

7 \ "kg"*9 \ "m"=55 \ "kg"*d_2

d_2=(7color(red)cancelcolor(black)"kg"*9 \ "m")/(55color(red)cancelcolor(black)"kg")

~~1.15 \ "m"