1997 Past Paper

[Suzy]

hi I'm really stuck on Qs 13 and 14 in the multiple choice - anybody know???
And, see how Impulse = mv - mu
what's m, v and u???
It's the one with P and Q, Q's initially at rest then after the collision Q moves right and P rebounds left
I can't find the change in momentum!? And then how do you draw the graph for Ft?
This papers really hard :/

[Admin]

m= mass, u = initial velocity and v = final velocity.
As for P and Q let mp = mass of p, mq =mass of q, up = initial velocity p, uq = initial velocity q, vp = final velocity p and vq = final velocity q.
conservation of momentum gives:
(mp x up) + (mq x uq) = (mp x vp) + (mq x vq). Just remember that they are velocities so direction matters.
Hope this helps wothout giving it all away.