At time t = t₀ a vertically oscillating spring-mass system is at its lowest point. At that instant gravity is switched off. Which graph correctly describes the subsequent displacement from the original equilibrium position?

Question

G1 Physics · Accepted Answer

Just before gravity is switched off the block is at the lowest point with zero velocity. Removing gravity shifts the equilibrium upward by mg/k but does not change ω=√(k/m). Relative to the new equilibrium, the initial displacement is larger than before and velocity is zero, so the subsequent sinusoid has the same period but larger amplitude and a shifted mean. The corresponding graph is option 4.