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My Question:

A 1500 kg car moving east at 38 m/s collides with a 1780 kg car moving south at 15 m/s and the two cars stick together.

(a) What is the velocity of the cars right after the collision? _______m/s ______^{o}

(b) How much kinetic energy was converted to another form during the collision? ______kJ

My attempt:

So i used the momentum formula and got the total momentum before collision and made it equal to the momentum after the collsion but didn't get the right answer.

Before collision: car1:

p=m1v1=(1500kg)(38m/s)=57000

car2:

p=m2v2=(1780kg)(-15m/s)=-26700

p1+p2=Ptotal

57000+(-26700)=30300

After collision: car1:

p=1500v1

car2:

p=1780v2

v1=v2 because of collision therefore

30300=(1500+1780)v

v=9.24m/s

when i took out the negative i got a different answer (25.5m/s) which was also wrong.

Part B i've no idea how to do:uhh:

Please tell me what i'm doing wrong!!!!!

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# Homework Help: Momentum .Please help

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