Answer to Question #161373 in Mechanics | Relativity for Samir khan

Question

You are driving in your car and have just purchased a tray of drinks which are sitting on the flat seat next to you. If you are travelling at 15.0 m/s and approach a turn with a radius of 30.0 m, what minimum coefficient of static friction is necessary to keep the drinks from sliding?

Answer 1

$$F_{fr}=F_c,$$ $$\mu mg=\dfrac{mv^2}{R},$$ $$\mu=\dfrac{v^2}{gR},$$ $$\mu=\dfrac{(15.0\ \dfrac{m}{s})^2}{9.8\ \dfrac{m}{s^2}\cdot30\ m}=0.76$$