Math Word Problems Demystified - A Self Teaching Guide

360

96

¼

961 x

961

3 : 75 ¼x

Hence she must sit 3.75 feet from the fulcrum.

EVALUATION: Check the equation:

WL¼wl

120 ð 3 Þ¼ 96 ð 3 : 75 Þ

360 ¼ 360

The fulcrum of a lever does not have to be at its center.

EXAMPLE:The fulcrum of a lever is 3 feet from the end of a 10-foot lever.

On the short end rests an 84-pound weight. How much weight must be placed

on the other end to balance the lever?

SOLUTION:

GOAL: You are being asked to find how much weight is needed to balance

the lever.

STRATEGY: Letx¼the weight of the object needed.

WL¼wl

84 ð 3 Þ¼xð 7 Þ

See Figure 16-3.

Fig. 16-3.

174 LESSON 16 Solving Lever Problems