What is the net magnetic field at a point due to perpendicular currents?

[thebigbluedeamon]

I cannot figure how this works..

A wire carries a 7.00 A current along the x-axis and another wire carries a 6.00 A current along the y-axis. What is the magnetic field at point p located at x=4.00m and y=3.00m.

Since each wire carries its own magnetic field, my instinct is saying that I just need to add the magnitude of the two fields. But that doesn't seem correct.

A speedy reply would be greatly appreciated.

 

[Doc Al]

Since each wire carries its own magnetic field, my instinct is saying that I just need to add the magnitude of the two fields. But that doesn't seem correct.

That's all there is to it. Be sure you have the correct sign (direction) of each field when you add them.

 

[thebigbluedeamon]

So would the direction of the field in the y-direction be negative and the direction in the x-direction be positive?

I guess I would end up with something like...

Bnet = Bx - By

Sounds easy enough for me.

 

[Doc Al]

So would the direction of the field in the y-direction be negative and the direction in the x-direction be positive?

The current along the y-axis creates a field (at the point in question) that is in the -z direction; the current along the x-axis creates a field in the +z direction.