
#19
Mar512, 11:42 PM

P: 158

http://www.realworldphysicsproble...ollision_8.png like this, i know all my momentum. but 150 does not equal 150 un less you set the equation to 0=150150 which equals 0. But what happened to the angular velocity??? don't i need to find like a magnitude in angular in velocity??




#20
Mar512, 11:48 PM

Mentor
P: 11,445

If you have two equal mass objects traveling with the same speeds in a headon collision and they stick together, what's their final velocity? By the way, the equation shown in your link is for elastic collisions, not inelastic. In a perfectly inelastic collision the two objects fuse  m1+m2. 



#21
Mar512, 11:52 PM

P: 158

0? but this 2 objects had different speeds! does i mean that doesn't matter how fast the objects are moving , when they stick together they both have 0 velocity??




#22
Mar512, 11:54 PM

Mentor
P: 11,445





#23
Mar512, 11:59 PM

P: 158

oh so it was only finding the moments of inertia to calculate angular momentum and use conservation of energy of inelastic collision??? that was it? ok now for part 2 i know the answer is 338 J




#24
Mar612, 12:01 AM

P: 158

If i sum up both of my KE rot they give me the answer, but here is my doubt why do i have to sum it up? don't I have to find the KE total and subtract that from KE rot f to get the kinetic energy lost??




#25
Mar612, 12:03 AM

Mentor
P: 11,445





#26
Mar612, 12:07 AM

P: 158

KE total is = 225J+112.5J
KEf=0 ??? 



#27
Mar612, 12:10 AM

Mentor
P: 11,445





#28
Mar612, 12:17 AM

P: 158

LOL no. So the KEf is 0 after all? I thought it was 0 because after the collision they both have no kinetic energy because they have no velocity. They both come to a stop. Don't know if my reason is indeed correct.




#29
Mar612, 12:20 AM

Mentor
P: 11,445





#30
Mar612, 12:21 AM

P: 158

thanks man! :D



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