A car is driving along a circular track of diameter d-0.95 km at a constant speed of v 22.5 m/s. Write an expression for the minimum coefficient of friction between the car's tires and the road that is required in order to keep the car going in a circle in terms of the given parameters

An insulated 40 ft^3 rigid tank contains air at 50 psia and 120°f. a valve connected to the tank is now opened, and air is allowed to escape until the pressure inside drops to 25 psia. the air temperature during this process is kept constant by an electric resistance heater placed in the tank. determine the electrical work done during this process.