Math Word Problems Demystified - A Self Teaching Guide

IMPLEMENTATION: Solve the equation:

84 ð 3 Þ¼ 7 ðxÞ

252 ¼ 7 x

252

7

¼

71 x

71

36 ¼x

36 pounds needs to be placed at the 7-foot end to balance the lever.

EVALUATION:

WL¼wl

84 ð 3 Þ¼ 36 ð 7 Þ

252 ¼ 252

EXAMPLE:Where should the fulcrum be placed on an 18-foot lever with a
36-pound weight on one end and a 64-pound weight on the other end?

SOLUTION:

GOAL: You are being asked to find the placement of the fulcrum so that the
lever is balanced.

STRATEGY: Let x¼the length of the lever from the fulcrum to the
36-pound weight and (18
x)¼the length of the lever from the fulcrum to
the 64-pound weight. See Figure 16-4.

The equation is

WL¼wl

36 x¼ 64 ð 18 
xÞ

Fig. 16-4.

LESSON 16 Solving Lever Problems 175