Physics Practice Problem: Accelerating with all-wheel drive An all-wheel drive (AWD) vehicle delivers torque to all four wheels of the vehicle. We want to find the acceleration of the vehicle. (a) The engine applies a torque to the wheels through a series of gears and shafts, but what force actually pushes the car forward? (b) Draw a force diagram for the whole car and a force diagram for one wheel. (c) Write down equations for the sum of the forces in each direction for the car. (d) Write down an equation for the sum of the torques on a single wheel. You can assume that the drivetrain divides the total applied torque (Tapp) evenly among all wheels, that all wheels are identical, and that each wheel is approximately a solid disk with mass. How do you relate the angular acceleration to the linear acceleration? (e) What is the acceleration of the car? (f) Should an energy-efficient car have small or large diameter wheels? Why? (g) Does friction play a role at all? If not, why not? If it does play a role, what type of friction, and what is the condition on the value of its coefficient?