Finding the Right Place for the Fulcrum
23) If a lever were 12 feet long, with 75 pounds on one end and
45 pounds on the other, where would the fulcrum have to be placed
to balance it?
75 * x = 45(12-x)
75x = 540 -45x
120x = 540
x = 4.5
The fulcrum would have to be placed 4.5 feet to the right of the
75 pound weight in order to have balance. (The 45-pound weight,
therefore, will be 7.5 feet from the fulcrum.)
We can also look at this in the following way to double-check
our answer:
75 (lbs) * 4.5 (feet from the fulcrum) = 7.5 (feet from
the fulcrum) * 45 (lbs)
337.5 = 337.5