# Physics Momentum

Could someone show me how to solve this question? Does A and B stick together after the collision?

Hi!
I think the bodies will stick post collision as it’s inelastic collision where bodies stick and have a same final velocity also in inelastic collision momentum is conserved but K.E isn’t.
Do you please mind sharing the answer as i’m not sure whether my calculation is correct or not.

I thought so too but I didn’t get an answer to what they said. The answer is 288N, if it matches, please show me!

Hi!
I got the value this is how i did it:
They have asked us the force dissipated so in order to calculate it we need “m” and “a” as F=m.a
the initial velocity was 15ms^-1 and the final velocity is 3ms^-1 post collision. thus, acceleration
a=v-u/t=3-15/0.5=-24ms^-2(negative because the body slowed down)
F=12*24=288N(considering only the magnitude).
Hope this helps!

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oh here’s how i found 288N:

p is conserved so:
delta p1 = F1 * delta t
so F1 = (m1 * delta v1) / delta t
so F1 = 12 * (3-15) / 0,5 = 288N

We consider the magnitude of delta V1 = +12

I think Ujjwal’s way is better

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hi!
Juliette i think your way is totally correct as i was getting a negative value so, i eventually considered only the magnitude as Forces are vectors.

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great catch let me change my answer i did Vi-Vf instead of the other way around, i guess we’ll just use the magnitude then?

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Thank you so much! I’ll keep this method in mind too when im rushed for time!

This makes a lot of sense! I think I went wrong in the last calculation where I used both the masses A and B to get Force

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