An unextended spring is in equilibrium. a mass m is placed at the end of it; the force of gravity causes the spring to extend. after a time a new equilibrium position is reached. if z is the extension of the spring, the force of tension is kx. obtain a formula for the extension of the spring when it is in equilibrium. what is the change in the potential energy of the mass? what is the increase in the internal energy of the spring? how much heat is released? what is the change in the entropy when a mass of 100g causes the spring to extend by 2, °c)? 5cm at room temperature 25