我来试试

Given:
Vg=40, Va=43, Vm=46, Vp=50, 7.5% difference
M1(5200 lb) is poor, M2(3200 lb) is good

Solution:
M1 以V=40 撞墙后完全停止，其Vi=40，Vf=0
delta P1=5200*40=208000，结果：poor

M2 以V=40 撞墙后完全停止，其Vi=40，Vf=0
delta P2=3200*40=128000，结果：good

如果以40对撞，完全非弹性碰撞（个人认为更接近实际情况）
M1*40+M2*(-40)=(M1+M2)*Vf
Vf=9.5

delta P1=5200*(40-9.5)=158600
result：
158600/208000=76%
decreased by 24%, from poor to good

delta P2=3200*(40+9.5)=158400
result：
158400/128000=1.23
increased by 23%, from good to poor

所有跟帖： 

• 完全正确 -BDXDL- ♂ (812 bytes) () 10/07/2014 postreply 10:32:10

• What's the second Vf? -MoonRiverMe- ♂ (76 bytes) () 10/07/2014 postreply 11:41:37

• 完全非弹性碰撞，两车碰撞完后， 速度都是Vf -BDXDL- ♂ (96 bytes) () 10/07/2014 postreply 11:54:34

• Your question indicates that you forgot high school physics some -CW62- ♂ (0 bytes) () 10/07/2014 postreply 12:27:16

• Wait a minute, let's see who forgot what after I got off work -MoonRiverMe- ♂ (0 bytes) () 10/07/2014 postreply 13:23:01

• let me ask one thing -MoonRiverMe- ♂ (357 bytes) () 10/07/2014 postreply 16:10:49

• Let me tell you -CW62- ♂ (608 bytes) () 10/07/2014 postreply 17:33:14

• This subject is meaningless to begin with -MoonRiverMe- ♂ (329 bytes) () 10/07/2014 postreply 19:08:08

• 別忙着下结论。车祸受伤是因为保险带没拉住人，气囊没挡住头，还是车身形变引起的？我看后者可能性大些。那样的话，经撞是很重要的。 -周老大- ♂ (0 bytes) () 10/07/2014 postreply 21:19:05

• What a funny logic -CW62- ♂ (694 bytes) () 10/08/2014 postreply 07:14:35

• you don't even know under what condition CM holds true -MoonRiverMe- ♂ (515 bytes) () 10/08/2014 postreply 16:37:57

• Are you serious? -CW62- ♂ (447 bytes) () 10/09/2014 postreply 07:42:18

• 他在同一个问题中用同一个Vf表达两个完全不用的量 -MoonRiverMe- ♂ (83 bytes) () 10/07/2014 postreply 15:41:05

• 仔细看看，Vf一直是velocity after collision，怎么表达两个完全不同的量了？ -CW62- ♂ (0 bytes) () 10/07/2014 postreply 17:54:31

• 不要和阅读能力有问题的较真啦，叫他自生自灭去吧～～ -修volvo- ♂ (0 bytes) () 10/11/2014 postreply 19:54:39