A certain mass m=8.00 kg is able to move in only one direction, which we call the x-axis. It has a potential energy given by this function: V(x)=Ax^2 − Bxx^3 where x is in meters, A=9.0 kg/s^2, and B=0.500 kg/(ms^2). This potential energy function is valid for all values of x, positive and negative. b) At a certain time, the mass is located at x=6.00 m, and has a velocity in the positive direction equal to 7.60 m/s. Assuming that it could be located at x=20.0 m at a different time, how fast will it be moving then?