Four long wires are perpendicular to the x-y plane. Each wire ...

[Jkov05]

Four long wires are perpendicular to the x-y plane. Each wire carries the same magnitude current. Wire 1 goes through point (a, a, 0) on the x-y plane, wire 2 goes through the point (a, a, 0), wire 3 goes through the point (a, a, 0), and wire 4 goes through the point (a, a, 0). Wires 1 and 3 carry their currents in the positive z direction and wires 2 and 4 carry their currents in the z direction. What is the direction of the resulting magnetic field at the origin?
 a. in the +x direction
  b. in the y direction
  c. in the x direction
  d. There is no direction since the field is zero at this point.

Question 2

The motion of a piston in an automobile engine is nearly simple harmonic. If the 1-kg piston travels back and forth over a distance of 12.0 cm, what is its maximum speed when the engine is running at 3000 rpm?
 a. 4.71 m/s
  c. 44.0m/s
  b. 9.42 m/s
  d. 22.0 m/s

[lou]

Answer to Question 1

D

Answer to Question 2

D

[Jkov05]

TYSM

[Joy Chen]

Excellent