How Does Collision Affect Car Velocity?

[tomwheeler87]

A car of mass 1348kg moving with a velocity of 26m/s collides with a car os mass 674kg moving with a velocity of 21m/s in the same direction. after they collide the 674kg car moves with a velocity of 5.25m/s


What is the velocity of the 1348kg object?


M1 = 1348kg
M2 = 674kg
V1 = 26ms-1
V2 = 21 ms-1

Ptotalbefore = P1before + P2before
Ptotalbefore = m1before * V1before + m2before * V2before
Ptotalbefore = 1348*26 + 674*21
Ptotalbefore = 49202kgms-1

Ptotalbefore = Ptotalafter
Ptotalbefore = P1after + P2after
49202 – (674*5.25) = P1after
P1after = 45663.6
P1after = m1after * V1after
P1after = V1after
M1after
V1after = 45663.6
......1348
V1after = 33.88ms-1


According to my answer car1 speeds up from 26m/s to 33.88m/s after the collision. I am certain that is not right but can't see where i have gone wrong can anyone help me please.

Thanks in advance
Tom

 

[VietDao29]

Uhmmm, the problem itself does not make much sense.
How come the 674 kg car moves with a velocity of 5.25 m / s after the collision? (5.25 m / s < 21 m / s).
Infact, after the collision, the 674 kg car should have a greater velocity than it had before the collision...
Viet Dao,

 

[whozum]

Your solution looks right, its the problem that doesn't make sense. When you get rear ended you don't slow down.

 

[tomwheeler87]

Cheers

Cheers people will have words at college tomorrow


Regards
Tom