1 100 N

2. 3 KN

3. frictional coefficient & the normal force (the component perpendicular to the motion direction).

4. < 196 N

5. a) 489.1 N

b) 455.6 N

c) 1205.23 N, 1122.68 N

6. both stopped (v = 0.026 m/s » 0).

7. 0.28 m/s (in the same direction of skater B’s velocity).

8. 0.7

9. work: 2800 J; power: 2240 watt; potential energy: 2800 J

10. a) 28 Ns

b) 28 Ns

c) 56 N