To calculate the final velocity of a 100kg object dropped from a height of 100m, use the principle of conservation of energy. The potential energy at height h is given by mgh, where g is the acceleration due to gravity. As the object falls, this potential energy converts entirely into kinetic energy at ground level. By setting the kinetic energy equal to the initial potential energy, you can solve for the final velocity. The final velocity can be calculated using the formula v = sqrt(2gh).