What Are the Forces at Play in Antarctic Snowcat Towing?

[milkywayiguana]

Homework Statement

Two snowcats in Antarctica are towing a housing unit north, (an example is shown in Figure 4-50 on page 102). Snowcat A pulls at an angle 49 o west of north, and snow cat B pulls at an angle 31 o east of north. The sum of the forces FA and FB exerted on the unit by the horizontal cables is north, parallel to the line L, and FA= 4633 N. Determine FB, and determine the magnitude of FA+FB.

2. Homework Equations
∑F=ma

The Attempt at a Solution

FA=4633N at 49
FB= xN at 31

FB(sin Θ)=FA(sin Θ)

FB(sin 31)=4633(sin49)

FB=4633(sin(49)/sin(31))

FB=6789

FB + FA=4633 + 6789
=11422

FB=6789
FB+FA=11422

My physics homework is online and requires me to plug the numbers in before automatically grading them. I plugged in 6789 and the answer was correct, however 11422 was wrong? Where did I mess up?

 

[Marc Rindermann]

Looks like you added the total forces. However, they point in different directions.

You were asked just to add the force components that point to the north.

 

[FactChecker]

Be careful when you translate "west of North" and "east of North" into angles. I think you did that wrong. I suggest that you draw a diagram of the vectors and their components to keep everything straight.

 

[kuruman]

Be careful when you translate "west of North" and "east of North" into angles.

Especially in Antarctica if you are at or near the South Pole.