Homework Help: Help with a tug of war problem

1. Jun 4, 2012

wbetting

1. The problem statement, all variables and given/known data
in a two-dimensional tug-of-war, Alex, Betty, and Charles pull horizontally on an automobile tire at the angles shown in the picture. The tire remains stationary in spite of the three pulls. Alex pulls with force of magnitude 211 N, and Charles pulls with force of magnitude 181 N. Note that the direction of is not given. What is the magnitude of Betty's force if Charles pulls in (a) the direction drawn in the picture or (b) the other possible direction for equilibrium?

** I got part a correct but i just do not understand what part b is looking for diagram link attached if doesn't work email.

http://i1148.photobucket.com/albums/o578/bettingw15/ScreenShot2012-06-04at95053AM.pn [Broken]

2. Relevant equations
for part a i used Fb= -fa-Fc
found angle of fa = 180-42= 138
fby=-fay-fcy
fbsin(-90)=-fasin138-fcsintheta
then did same thing with x components to get angle theta= 29.97 then plugged that angle into formula -fb=-(211N0(sin138)-181N(sin 29.97)
= 321.60 N

I understand that but how do i do the other possible direction? The question does not even make sense to me

3. The attempt at a solution

Last edited by a moderator: May 6, 2017
2. Jun 4, 2012

Villyer

The image isn't showing for me.