Calculating Resultant Force: Understanding the Error

[Luongo]

1. If the resultant force acting on the hook is F_R = <-180, 810, 180> what is the magnitude of F?



2. So basically i got F1 which is <240,416,-360> and subtracted this from FR and got vector F2 then i took the square of the components and square rooted getting 789lb. Why is this wrong? what am i doing wrong?



3. Please tell me why i got the wrong answer it should be right

 

[tiny-tim]

Hi Luongo!

I get 789 also.

(Are you sure it's 810 for F_Ry? It doesn't look like that in the diagram)

 

[Altabeh]

1. If the resultant force acting on the hook is F_R = <-180, 810, 180> what is the magnitude of F?



2. So basically i got F1 which is <240,416,-360> and subtracted this from FR and got vector F2 then i took the square of the components and square rooted getting 789lb. Why is this wrong? what am i doing wrong?

Tell us how'd you get F1_x and F1_y!?

 

[Luongo]

Tell us how'd you get F1_x and F1_y!?

to get those two i got F' which is the angle perp to the F1_z component then used that as a coefficient

 

[Luongo]

Hi Luongo!

I get 789 also.

(Are you sure it's 810 for F_Ry? It doesn't look like that in the diagram)

Yes it's right, i got the units wrong...? DAMN MASTERING PHYSICS! crap... lol