A spring with spring constant has a 2.5 times 10^4 N/m has a 1.4-kg cart at its end. (a) If its amplitude of vibration is 0.030 m, what is the total energy of the cart + spring system? (b) what is the maximum speed of the cart? (c) If the energy is tripled, what is the new amplitude? (d) What is the maximum speed of the cart? (e) What assumptions did you make to solve the problem? If the assumptions were not reasonable, how would the answers change?