A busy chipmunk runs back and forth along a straight line of acorns that has been set out between his burrow and a nearby tree. At some instant the little creature moves with a velocity of -1.45 m/s. Then, 2.55 s later, it moves at the velocity 1.85 m/s. What is the chipmunk\'s average acceleration during the 2.55-s time interval? a) 0.16 m/s
b) 0.73 m/s
c) 1.29 m/s
d) 2.28 m/s