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?

Answer 1

sum moments about the fulcrum...

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

solve for L

Answer 2

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

which one ?

Answer 3

1.93m

Answer 4

The answer is 1.98, not sure why.

Answer 5

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