(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Two particles have mass 0.12kg and 0.08kg respectively. They are intially at rest on a smooth horizontal table. Particle A is then given an impulse in the direction AB so that it moves with speed 3m/s directly towards B.

Immediately after the particles collide the speed of A is 1.2m/s, its direction of motion being unchanged.

(c) find the magnitude of the impulse exerted on A in the collision.

2. Relevant equations

impulse = change in momentum (mv-mu)

3. The attempt at a solution

(c)

I get

impulse = mv-mu

= (0.12 x 1.2) - (0.12 x 3)

= - 0.216 Ns

But the mark scheme said the answer is + 0.216 Ns ... how can this be if the velocity after is less than the velocity before, i don't understand why??

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# Homework Help: Impulse and momentum of two particles

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