Within the green dashed circle shown in the figure below, the magnetic field changes with time according to the expression $B = 9.00t^3 - 3.00t^2 + 0.800$, where $B$ is in teslas, $t$ is in seconds, and $R = 2.45$ cm.
(a) When $t = 2.00$ s, calculate the magnitude of the force exerted on an electron located at point $P_1$, which is at a distance $r_1 = 4.90$ cm from the center of the circular field region.
N
(b) When $t = 2.00$ s, calculate the direction of the force exerted on an electron located at point $P_1$, which is at a distance $r_1 = 4.90$ cm from the center of the circular field region.
tangent to the electric field line passing through point $P_1$ and clockwise
tangent to the electric field line passing through point $P_1$ and counterclockwise
The magnitude is zero.
(c) At what instant is this force equal to zero? (Consider the time after $t = 0$ s.)
s
