A uniform rod of length 10 meters and mass 20 kilograms is balanced on a fulcrum with a 40 kg mass on one end of the rod and 20 kg mass on the other end, as shown above. How far is the fulcrum located from the center of the rod?
B. 1 m
C. 1.25 m
D. 1.5 m
E. 2 m
(GR9277 #100)
Solution:
∑τ = 0
200(5+d) + 200d - 400(5-d) = 0
1000 + 200d + 200d - 2000 + 200d = 0
800d = 1000
d = 10/8 = 1.25
Answer: C
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