A small object with mass m = 0.0900 kg moves along the +x-axis. The only force on the object is a conservative force that has the potential-energy function U(x) = −αx^2 + βx^3, where α= 5.00 J/m^2 and β = 0.300 J/m^3. The object is released from rest at small x. When the object is at x = 4.00 m, what are its:
(a) speed and (b) acceleration (magnitude and direction)?
(c) What is the maximum value of x reached by the object during its motion?