Figure-7 shows the cross-section of a hollow cylinder of inner radius a = 4.00 cm and outer radius c = 9.00 cm. A uniform current density of 2.50 A/ cm2
flows through the cylinder parallel to its axis.
What is the magnitude of the magnetic field at = 2.00 cm?

Two students, each riding bicycles, start from the same apartment building and ride to the same building on campus, but each takes a different route. the first student rides 1100 m due east and then turns due north and travels another 1430 m before arriving at the destination. the second student heads due north for 1930 m and then turns and heads directly toward the destination.at the turning point, how far is the second student from the destination?