A bear leaves its den and begins foraging for food. It takes 20 minutes to move 1.2 km north, then spends 42 minutes traveling 1.35 km at an angle of 54 degrees east of north. From there it walks 2.1 km at an angle of 29 degrees south of west before reaching a berry bush. The last leg of the trip lasts an hour and 18 minutes.
a. What is the average velocity of the bear from the den to the berry bush?
b. If the bear wishes to return to the den by moving in a straight line, how far and in what direction relative to north must it travel?
c. What is the bear's average acceleration between t = 40 minutes and t = 2 hours?