A coaxial cable consists of an inner cylindrical conductor of radius 3 cm on the axis of an outer hollow cylindrical conductor of inner radius 7 cm and outer radius of 10 cm. The inner conductor carries current 4.5 A in one direction, and the outer conductor carries current 8 A in the opposite direction. (a) What is the value of the magnetic field at distances 8 cm and 20 cm from the axis of the cable? (b) Draw how the magnitude of the magnetic field changes with the distance from the axis of the cable.

One hazard of space travel is debris left by previous missions. there are several thousand masses large enough to detect by radar orbiting the earth, but there are far greater numbers of very small masses such as flakes of paint. calculate the force exerted by a 0.110 mg chip of paint that strikes a space shuttle window at a relative speed of 5.00 ✕ 103 m/s and sticks, given the collision lasts 6.00 ✕ 10-8 s. such a collision chipped the window of the ill-fated challenger in june 1983, causing $50,000 of damage.