The force exerted by a pulley is the sum of the tension and the force of gravity. Since a pulley is used to lift something, the force is negative. The tables show the tension, T(m), and the force of gravity, G(m), for objects of various masses, m in grams, all accelerating upward at 2.5 m/s2.The force of the rope is equal to the negative of the sum of the rope’s tension and the force of gravity.