The potential energy function associated with a force acting on a system is U = 3x'y - 8x. What is the force at point (x, y)? (Express your answer in vector form.) F = Need Help? Read It 10. [-/1 Points] DETAILS SERPSE10 7.XP.004. A 11.0 kg block is dragged over a rough, horizontal surface by a 93.0 N force acting at 20.00 above the horizontal. The block is displaced 4.00 m, and the coefficient of kinetic friction is 0.300. [a) Find the work done on the block by the 93.0 N force. (b) Find the work done on the block by the normal force. (c) Find the work done on the block by the gravitational force. (d) What is increase in internal energy of the block-surface system due to friction? (e) Find the total change in the block's kinetic energy.A 450-N child is in a swing that is attached to a pair of ropes 1.80 m long. Find the gravitational potential energy of the child-Earth system relative to the child's lowest position at the following times. (a) when the ropes are horizontal (b) when the ropes make a 31.00 angle with the vertical (c) when the child is at the bottom of the circular arc Need Help? Read It Watch It