(29-54) In a circular region, there is a uniform magnetic field B pointing into the page (Fig. 29-47

(29-54) In a circular region, there is a uniform magnetic field B pointing into the page (Fig. 29-47). An xy coordinate system has its origin at the circular region’s center. A free positive point charge +Q=1.0μC is initially at rest at a position x=+10cm on the x axis. If the magnitude of the magnetic field is now decreased at a rate of −0.10T/s, what force (magnitude and direction) will act on +Q?

[manatee]

In the final equation for force, I believe it should be (r/2) instead of (pi*r^2)