A 30.0-kg child sits on one end of a long uniform beam having a mass of 20.0 kg, and a 43.0-kg child sits on the other end. The beam balances when a fulcrum is placed below the beam a distance of 1.10 m from the 30.0-kg child. How long is the beam?

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  1. sum moments about the fulcrum...

    1.1*30-(L-1.1)43 - 20(L/2 -1.1)=0

    solve for L

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  2. a. 2.12 m
    b. 2.07 m
    c. 1.98 m
    d. 2.20 m
    e. 1.93 m

    which one ?

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  3. 1.93m

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  4. The answer is 1.98, not sure why.

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  5. 1.93 m is the correct ans. If you take 40 kg mass instead 43 kg, then you will get 1.98 m.

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