A cup of coffee is on a table in an airplane flying at a constant altitude and a
ID: 2228223 • Letter: A
Question
A cup of coffee is on a table in an airplane flying at a constant altitude and a constant velocity. The coefficient of static friction between the cup and the table is 0.170 . Suddenly, the plane accelerates forward, its altitude remaining constant. What is the maximum acceleration that the plane can have without the cup sliding backward on the table? Use g = 9.81 m/s2.Explanation / Answer
You must solve this problem in terms of the variables associated with the questions, or you can estimate the weight of the cup of coffee. the sum of all forces in the x direction is F = 0 = ma - (mu)*N mu is the coefficient of friction N is the normal force = mass of cup * the acceleration due to gravity. lets assume the mass of the cup is 300 g. ------> 170*a = .30*(170* 9.8 m/s^2) a = 2.94 m/s^2 as you can see the mass of the cup does not even matter. It could be anything and youd still get the same maximum acceleration. The plane accelerating forward can be equivicated to the cup accelerating backward, which is why you can use the mass in F= ma as the mass of the cup