An object is thrown vertically upward. Its initial speed is 13 m/s and its initial height is 0 m. As the object moves, the only force acting on the object is force of gravity (viscous/friction forces can be neglected). (a) Determine the maximum height above the ground level the object will reach. (b) If the mass of the object is 7500 grams, calculate the gravitational potential energy of the object, in kJ, relative to the surface once it reaches the maximum height. Assume that the gravitational acceleration is g = 9.81 m/s. m1 V