Randall D. Knight — Dynamics I: Motion Along a Line: Problem 53

While driving to work one day, I was holding my coffee mug in my left hand while changing the radio station with my right hand. Then my cell phone rang, so I placed the mug on the flat part of my dashboard. Then, believe it or not, a deer ran out of the woods and onto the road right in front of me. Fortunately, my reaction time was zero, and I was able to stop from a speed of 22 m/s in a mere 50 m, just barely avoiding the deer, without the coffee mug sliding. What is the minimum possible value of the coefficient of static friction between the mug and the dashboard? The mug (with coffee) had a mass of 550 g, and the mass of the deer was 150 kg.