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1.
A
B
C
D
BD
2. 0.05 kg 20 m/s
20 m/s p p
Ap p=1 kgm/s(1kgm/s)=2kg m/s
Bpp1kgm/s1kgm/s=2kgm/s
Cp p=1kgm/s1kgm/s=2kgm/s
Dpp=1 kgm/s1kgm/s=0
A
3.
A B
C D
D
4. m t
A mgt Bmgt C0 D mgt/2
A
5. m t f
A(mg+f)t Bmgt C(mg-f)t D
D
6. F t F
A0 BFt Cmgt D
B
