I am having a bit of trouble with question 1c in the OCR 2824 June 2008 paper - the question about collisions between three objects.
Could someone explain to me how we know straight away for part 2 that block 1 just bounces back and moves in the opposite direction. I can show that mathematically but I wouldn't know how to do it without setting up simultaneous equations etc... Is there a more intuitive way? Also for part i, I thought the answer would be along the lines of, 2 and 3 can't remain stuck as the collision is elastic, so 3 must move off and as it has the same mass as 1, its velocity must be the same to conserve momentum, but I feel like this isn't true since 2 and 3 are stuck together in part ii and this is still an elastic collision.
Thank you for any help anyone can give me. I know this is basic stuff but it is better to be sure than to regret asking.
If anyone has time, I am also having a bit of trouble with 2d since I thought the KE of the glider would be zero at t = 0 due to the velocity being zero, but the mark scheme says the graph should be a negative cosine graph... What am I thinking about wrong?