While you are packing up to drive to school, you forget your laptop on the roof of your car. As you are driving west towards school at v = 45 mi/hr, you suddenly remember the laptop, roll down your window, and put your hand on the laptop exerting a force of 50 N downward and 20 N horizontally toward the rear of the car on the laptop, and hit the brakes. The coefficient of static friction of between the laptop and car roof is 0.4. The mass of the car is 1200 kg and the mass of the laptop is 4 kg.
(a) Draw the free body diagram of the laptop. Label ALL forces acting on it. Label your coordinate axes defining your directions.
(b) What is the maximum acceleration (magnitude AND direction) that can be applied to the car so that the laptop does not end up in several pieces on the pavement?