A circular coil with a diameter of 100 mm, which is at the same plane as the one of the sheet, conducts a current of 6A counterclockwise. The coil is immersed in a material of relative permeability of 2.5. Find the magnitude of the magnetic induction,
a) at the center of the coil and
b) 3 cm away in the center axis.

Aperson gives a shopping cart an initial push along a horizontal floor to get it moving, and then lets go. the cart travels forward along the floor, gradually slowing as it moves. consider the horizontal force(s) on the cart while it is moving forward and slowing. which of the following statements is correct? (a) both a forward and a backward force are acting on the cart, but the forward force is larger. (b) only a forward force is acting which diminishes with time. (c) both a forward and a backward force are acting on the cart, but the backward force is larger. (d) only a backward force is acting, no forward force.