# physics

posted by .

A high-voltage line of length 175 m is carrying a current of 105 A at a point on the earth where its magnetic field is 5 * 10^(-5) T and points North,34 degree from the vertical axis.
A) what is the magnitude and direction of the force on the wire if the current is flowing horizontally to the North?
HINT: horizontal is 90 degree from the vertical axis. Also, it may keep your brain from hurting too much by drawing the two dimensional "North- vertical" plane.
B)What is the magnitude and direction of the force on the wire if the current is flowing horizontally to the east?
Hint: Again the North-vertical plane is your friend.

• physics -

I recall answering this yesterday. I left the final steps for you to do. Please check your previous post.

The answer requires multiplying B (the magnetic field), I (current), L (wire length) and the sine of 56 degrees, the angle between the current and the B vectors

• physics-to drwls -

how can we do the B part of the question...

• physics -

B) If the current is horizontal to the east, and the B field remains inclined 34 degrees to verical, pointed north, B and I are perpendicular. The force is B I L without any sine or cosine factor. The direction of the force will be perpendicular to both, in the north-south vertical plane, but inclined upward 34 degrees from the horizon plane of the earth. Use the right-hand rule when forming I x B