Question

Debbie weighs 96 pounds and Denise weighs 120 pounds. They are seated at opposite ends of a seesaw. Debbie and Denise are 16.5 feet apart, and the seesaw is balanced. How far is Debbie from the fulcrum?

Answer 1

Explanation:

Let d be Debbie's distance from the fulcrum. Then Denise's is (16.5 - d) ft.

Torque is measured in (distance)(force). Here, that'd be (distance)(weight).

Here:

96d = 120(16.5 - d), or 96d = 1980 - 120d

Adding 120d to both sides yields:

216d = 1980, so that d = 9 1/6 ft. This is how far Debbie sits from the fulcrum

Denise sits (16 1/2 ft - 9 1/6 ft) from the fulcrum: This works out to 7 1/3 ft. Her being heavier requires that she sit closer to the fulcrum than Debbie.

Debbie sits 9 1/6 ft from the fulcrum, and Denise 7 1/3 ft.