33. An unusual spring has a restoring force of magnitude F = (2.00 N/m)x + (1.00 N/m2 )x 2 , where x is the stretch of the spring from its equilibrium length. A 3.00 kg object is attached to this spring and released from rest after stretching the spring 1.50 m. If the object slides over a frictionless horizontal surface, how fast is it moving when the spring returns to its equilibrium length? (A) 5.84 m/s (B) 4.33 m/s (C) 2.06 m/s (D) 5.48 m/s (E) 1.50 m/s