Understanding projectile motion under gravity, calculating time of flight, speed before impact, calculating speed after an inelastic collision (loss of speed), and calculating the maximum height reached with a new initial velocity. Ans: A - Density is mass per unit volume. - When mixing, total mass is the sum of individual masses, and total volume is the sum of individual volumes (assuming no volume change upon mixing, which is typical for miscible liquids unless otherwise specified). - The calculation is based on the given condition that the liquids have the 'same volume'.