Minimizing a vector in a triangle

[Shaybay92]

Homework Statement

A truck is to be towed using two ropes. If the resultant force is to be 950N, directed along the positive x axis, determine the magnitudes of forces F1 and F2 acting on each rope and the angle at which rope two pulls to ensure that the magnitude of F2 is a minimum. F1 acts at 20 degrees from the x axis.

The Attempt at a Solution

I assumed that to minimize the work required by rope two, it would be -90degrees angle (so it is only required to pull the truck back in line). However, the book says -70degrees?

 

[tiny-tim]

Hi Shaybay92!

(have a degree: º )

I assumed that to minimize the work required by rope two, it would be -90degrees angle (so it is only required to pull the truck back in line). However, the book says -70degrees?

Sorry, no idea what you mean.

Anyway, just draw a vector triangle …

you know the direction and length of one side, and you know the direction of the second side …

what is the shortest the third side can be? ​

 

[ghost2]

I'm assuming based on the wording that there's a diagram that goes with this? It's kinda hard to solve a geometry problem if there's supposed to be a picture with it.