12) A pendulum that consists of a 2 kg mass swings to a maximum vertical displacement of 17 cm above the rest position. At its lowest point, the kinetic energy of the mass is equal to; a) 0.33 J b) 3.33J c) 33.3 J d) 333] e) 3,333] 13) A box is pulled along a smooth floor by a force F, making an angle o'with the Horizontal. As 0' increases, the amount of work done to pull the box the same distance, d, is; a) Increases b) increases then decreases c) remains constant d) decreases then increases e) decreases 14) As the time needed to run up a flight of stairs deceases, the amount of work done by gravity; a) Increases b) decreases c) remains constant 15) An object moves at a constant speed in a circular path. Which one of the following is true. a} velocity vector is constant b) acceleration vector is constant c) net force on object is zero d) acceleration vector always points towards center of the circle