My friend invented a new dog leash called the X-R leash. It is made of a top secret material that exerts a force of Fx= -kx- ax2 when it is stretched a distance x, where a and k are constants.
Determine the work done on a dog by the leash if the person remains stationary, and the dog bounds off, stretching the X-R Leash from x= 0 to x=x1.