Mathematical addition of forces. PLZ HELP!!?

Question

i learnt to write the direction and amount of force on a X and Y axis, and the q i have involves 4 forces one at (A)30 degrees from the -X axis,(B) one at 30 from the +X degrees, (C)one that runs along the both the + and - side of the X axis and (D)one hat runs from just the - side of the y axis. but 2 add these up to see the total force in play i need to no that degrees c and d are on? i tried 90degrees and 0 degrees, but dont no what is right? plz help!!

Answer 1

You need to go back and study rectangular to polar co-ordinate conversion.  Then express each of the forces in rectangular (x,y) magnitudes.  Once you get all of that done, just add up the x magnitudes from each force to get the total x magnitude of the resultant force and all of the y magnitudes of each force to get the total y magnitude of the resultant.  If the problem asks for the magnitude and direction of the resultant force, then you'll have to convert the resultant from rectangular to polar co-ordinates.

That's the reason you learned to do polar-rectangular co-ordinate conversion.

HTH,

Doug