Amotorcyclist is traveling along a road and accelerates for 4.84 s to pass another cyclist. the angular acceleration of each wheel is 6.76 rad/s2, and, just after passing, the angular velocity of each is 77.6 rad/s, where the plus signs indicate counterclockwise directions. what is the angular displacement of each wheel during this time?

Athin electrical heater is inserted between a long circular rod and a concentric tube with inner and outer radii of 20 and 40 mm. the rod (a) has a thermal conductivity of ka = 0.15 w/(m*k), while the tube (b) has a thermal conductivity of kb = 0.8 w/(m*k) and its outer surface is subjected to convection with a fluid of temperature t= -15°c and heat transfer coefficient 60 w/(m2 *k). the thermal contact resistance between the cylinder surfaces and the heater is negligible. (a) determine the electrical power per unit length of the cylinders (w/m) that is required to maintain the outer surface of cylinder b at 15°c. (b) what is the temperature at the center of cylinder a?