Problem 4: A 5-kg object is moving in a x-y plane. At time t=0, the box crosses the origin travelling with the speed of 9m/s in the + x direction. It is subjected to a conservative force, which hast the following potential energy function associated with it: U(x.y) = 60y - 4x2+ 125 (units have been omitted, you can assume putting x and y in meters gives U in joules) The forces acts on the box for exactly one second, at which time it has moved to a position given by the coordinates x=11.6 m and y= -6.0m. 4.1: (5 points) Find the speed of the object at the end of the one-second interval. 4.2: (5 points) Find the acceleration of the object at the end of the one-second interval. Express your answer in terms of magnitude and direction