The potential energy curve of a 2 kg object is shown. If the total energy is 4 joules, then the speed of the object at X3 is: ), E (J) W x2 Select one: x3 a. 0.0 m/s b. 0.5 m/s c. 1.0 m/s d. 1.5 m/s e. 2.5 m/s x4 x5