In the magnetic circuit shown in Figure 21.18, the second coil carries a current of 2 A. If flux in the core is to be made zero, the current I in the first coil should be (A) +4 A (B)-2 A (C) - 4 A (D) +2 A

Arunner is training for an upcoming marathon by running around a 100-m-diameter circular track at constant speed. let a coordinate system have its origin at the center of the circle with the x-axis pointing east and the y-axis north. the runner starts at (x, y) = (50 m, 0 m) and runs 2.5 times around the track in a clockwise direction.

What causes the formation of ocean currents?

What is the orbital period of a spacecraft in a low orbit near the surface of mars? the radius of mars is 3.4×106m.