An advertisement for a "No-Spill Travel Mug" claims: "Thanks to inertia
PHYSICS · Multi-part · CBSE · Physics · Laws of Motion · Laws of Motion
Problem
An advertisement for a "No-Spill Travel Mug" claims: "Thanks to inertia, the beverage inside remains perfectly undisturbed even when the bus takes a sharp turn; spills are impossible." Consider a bus negotiating a horizontal curve of radius 15 m at a steady speed of 10 m s⁻¹ while a passenger holds the filled mug upright.
(i) Using suitable physical reasoning, comment on the correctness of the manufacturer’s claim that inertia alone prevents the liquid from spilling during the turn.
(ii) Calculate the magnitude of the lateral (centripetal) acceleration experienced by the mug–and therefore by the liquid–while the bus turns.
(iii) If the beverage has a mass of 0.25 kg, determine the corresponding lateral force acting on it.
(iv) Based on your answers to parts (ii) and (iii), discuss whether the liquid surface would stay level relative to the mug or tilt, and hence judge the likelihood of spillage.
(v) Suggest one practical design feature (other than merely relying on inertia) that could genuinely help to prevent spilling in such situations.