Finding net magnetic field by subtracting two fields

[Spectre32]

alright... i just figured out two magnetic fields, and now the question is asking me to find out the net magnetic field and the direction, for the net i would just subtract the biggest from the smallest, and then i use the Right hand rule to figure out the direction of the B field... is this correct.

 

[cookiemonster]

Try vector addition, not a combination of vector addition and the cross product.

cookiemonster

 

[Spectre32]

so u mena like set the bigge one - the smaller one = 0?

 

[cookiemonster]

It doesn't matter which one's bigger or smaller.

You are familiar with vector addition, correct?

$$\vec{v} = <v_x,v_y>$$
$$\vec{v} + \vec{u} = <v_x,v_y> + <u_x,u_y> = <v_x + u_x,v_y + u_y>$$

And bigger - smaller = 0 would imply that bigger = smaller, just for reference.

cookiemonster

 

[HallsofIvy]

so u mena like set the bigge one - the smaller one = 0?

No, when he said "try vector addition", believe it or not, he actually meant "add". You already know the two fields separately- the "net" force field is exactly the same as the sum- if the two forces are in the same direction, then the "net" force is "larger" (in strength)- if they are in opposite directions, the sum is smaller (in strength). In any case, the vector properties will take care of that- just add the vectors.