13. How much work is done by a person pulling an object on a frictionless surface, if the pulling force is 200 N at a 28 degree angle with the vertical. The object is supposed to move on a distance of 25.0 m. t Add file 14. A mass of 0.500 tonnes is placed on a forklift that can generate 0.980 kW of * power. What is the constant lifting speed of the forklift ? t Add file 15. A rock that started falling from an initial height of 80 m is moving at a speed * of 10m/s. The mass of the rock is 50 g. Calculate the height at which the rock is moving at 10m/s. Use the law of conservation of energy. 1 Add file