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A2 Physics - Momentum - CLUELESS watch

1. I have no idea if I'm doing any of these questions right. If someone could help me out I'd appreciate it a lot. Thank you.

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2. The first one's wrong. Momentum is conserved so you can setup the equation as: m1v1 = m2v2 hence, v2 = (m1v1)/m2
Which gives v2 as 0.23m/s (2 d.p.)

Also think about it logically, if the initial speed was 0.24m/s it would definitely not be 4.8m/s after colliding.

I tried the rest got: b, 0.2m/s c, 400kg.m/s 4, 3.67m/s
3. I'm slightly confused is m1 not 1.0x10^4kg? And v1 = 0.24ms-1? So if I use the equation m1v1 = m2v2. V2 = (m1v1)/m2. V2 = (1.0x10^4 x 0.24) / 500 = v2. V2 = 4.8? :/

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4. (Original post by ohnanailikenanas)
I'm slightly confused is m1 not 1.0x10^4kg? And v1 = 0.24ms-1? So if I use the equation m1v1 = m2v2. V2 = (m1v1)/m2. V2 = (1.0x10^4 x 0.24) / 500 = v2. V2 = 4.8? :/

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I think you've just misunderstood the setup.

AFAICT The engine and the first truck are stuck together so m2 is 1500kg
5. I'm still getting a weird answer though. Ugh. I used v2 = (1.0x10^4 x 0.24)/1500 and I got 1.6ms-1. The guy above got 0.23ms-1 :/
6. sorry man, m2 is 10500 not 1500
7. (Original post by ohnanailikenanas)
I'm still getting a weird answer though. Ugh. I used v2 = (1.0x10^4 x 0.24)/1500 and I got 1.6ms-1. The guy above got 0.23ms-1 :/
The mass of the engine is 10,000(1x10^4) not 1,000.
8. Yeah I got it eventually, thanks everyone

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Updated: September 16, 2015
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