1. A box of mass m kg slides at a speed of vo m/s across a smooth level floor, where it enters a rough portion L m in length. In the rough portion, the box experiences a horizontal frictional force (the frictional coefficient equals u). a. How much work is done by the frictional force? b. What is the velocity of the box when it leaves the rough surface? c. What length of rough surface brings the box completely to rest? 2. A 1300-kg car is to accelerate from rest to a speed of 30 m/s in a time of 12 s as it climbs a 15 hill. Assuming uniform acceleration, what minimum power is needed to accelerate the car in this way? 3. Jane, looking for Tarzan, is running at top speed and grabs a vine hanging vertically from a tall tree in the jungle. How high can she swing upward? Does the length of the vine affect your answer? Consider different scenarios. Explain your reasoning. 4. A block m is dropped from a height of H onto a spring of force constant k. Find the maximum distance the spring will m be compressed. H