6. Imagine that a group records the following position vs. time graph with a motion detector. Position. meters '3 0.5 1.0 1.5 _.0 2.5 310 T1111e,5ecc)lld5 a. Does the object ever have a positive acceleration? If so. describe the time interval or intervals and explain how you can tell. If not. explain why not. 13. Does the object ever have a negative acceleration? If so. describe the time interval or intervals and explain how you can tell. If not. explain why not. c. At approximately t=l .? s the object changes direction. Is the acceleration at this instant positive, negative. or zero? Explain. d. Calculate the velocity of the object at time 2.5 seconds. Be sure to show your work. e. Calculate the velocity of the object at time 1.0 second. Be sure to show your work