D
6
A B C D
7
A6m/s B3m/s C1m/s D0.5m/s
8 F x 4cm
8cm
A.0.6 J -0.6 J
B.-0.6 J 0.6 J
C.1.8 J -1.8 J
D.-1.8 J 1.8 J
9 a b
A.b a
B.
C. a b
D. a b
10 ,
A
B
C
D
11 F m l F
W1 2m l
F W
2
AW
1W
2BW
1W
2CW
1W
2D
12
PP m O
