Year 12s: what will be the first way you research your future options? >>

linear momentum

svirdi

Question 6

My answer: please tell me where I have gone wrong?

Original post by svirdi

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First part is fine, excepting when you rounded 0.26666666, it's not 0.26. I'd leave it as 4/15, which is exact.

In the second part you're dealing with Arnold, the trolley, and the package, so:
Just before the package is thrown back, mass (50+20+ 5) with a velocity of 4/15 ms-1

Then afterwards, the package is going at -5, as it's in the opposite direction.

Have another go.

Aside: I have assumed that it's going at -5ms-1 relative to the air, not that he threw it at -5ms-1. The latter would imply a different velocity as he's already travelling at 4/15 ms-1, and overly complicate the question, which I suspect is not what was intended - but I could be mistaken.