Mass of bottle + cooking oil = 1.3 kg Mass of bottle + 1/2 cooking oil = 0.9 kg Thus half cooking oil = 1.3 - 0.9 = 0.4 kg Mass of cooking oil in a full bottle = 0.4 × 2 = 0.8 kg Therefore the mass of the empty bottle = 1.3 - 0.8 = 0.5 kg
Assuming the light takes essentially no time to reach you, the distance at which the lightning occurred can be calculated by multiplying the speed of sound by the time it takes to hear the thunder:
