16) A force F of strength 20N acts on an object of mass 3 kg as it moves a Distance of 4 meters. If F is perpendicular to the 4m displacement, the work the force does is; a) 0 b) 80 c) -80 d) can't be determined 17) Under the influence of a fore, an object of mass 4 kg accelerates from 3 m/s to 6 m/s in 8 seconds. How much work was done on the object during this time? a) 0 b) 54 c) 108 d) 96 18) A force of 200N is required to keep an object sliding as a constant speed of 2 m/s across a rough floor. How much power is being expended to maintain this motion? a) 200 b) 400 c) 800 d) can't be determined 19) A spring is compressed a distance of 0.10 m from its rest position and held in pace while a 0.10 kg ball is placed at its end. When the Spring is released, the ball leaves the spring traveling at 10m/s. What is the spring's spring constant k? a) 10 b) 100 c) 1000 d) 10000 20) To objects, both of mass 5kg are placed 5 meters from each other. What is the gravitational force felt by each object? a) 1 N b) 10 '10 N c) 0.667 N d) 6.67 X 10'11 N