2019-2020
1
A
B
C
D
2 8 N
12 N 10 N f
fm
Af=12Nfm
=8N Bf=10Nfm
=12N
Cf=10Nfm=12N Df=10Nfm=8N
3 ( )
A B C D
4
( )
A
B
C
D
5 R N ABAB
3R A 4mB m
g A N B
AmgR B1.2mgR C1.4mgR D1.6mgR
6 , 3 kg .
, 6 N, 15 N,
( )
