Terminal velocity depends on density difference Steps: - Terminal velocity is reached when drag force balances net downward force (weight minus buoyancy). - Weight = mass × g, where mass depends on ball's density (ρ_b); buoyancy depends on liquid's density (ρ_l). - Drag force depends on velocity, viscosity (η), and ball size, but terminal velocity v_t balances at a constant speed independent of starting conditions. - From Stokes' law, v_t = [2 r² g (ρ_b - ρ_l)] / (9 η), showing dependence only on ρ_b and ρ_l (plus fixed factors like g, r, η). - Drop height (1) affects acceleration time but not equilibrium v_t. - Liquid depth (4) must be sufficient to reach v_t, but doesn't alter its value. Why 2 and 3 affect terminal velocity: - v_t formula shows direct proportionality to (ρ_b - ρ_l), so increasing ρ_b raises v_t; increasing ρ_l lowers it by boosting buoyancy. Why the others are wrong: - A: Height (1) irrelevant to force balance. - B: Height (1) irrelevant to force balance. - C: Depth (4) irrelevant to force balance. - D: …