Is Momentum the Key Factor in Impact for Elastic Collisions?

[KaneOris]

Hey guys, I am a new member here and i don't know that much about physics so if this seems really obvious to you sorry, I am only 15!

Ohk here's my problem.
I was looking at some stuff on impact
Now impact is reliant on impulse yes?
Now if I(impluse) = F average * change in time
And impulse is = momentum
momentum is Mass * Acceleration, or delta v / delta t
So if a bird is traveling at a velocity of 10m/s with a mass of 10kg but has no acceleration and it collides with an aeroplane which is traveling at 80m/s with a mass of 12 tons with no acceleration does that mean there is no impact as there is no acceleration?

 

[Tide]

When they collide each object undergoes acceleration - the bird more so than the airplane! :-)

 

[KaneOris]

Oh i see, it all makes sense now thnx

 

[KaneOris]

oh I am an idiot i see now, p = mv, not ma, ma is f... oh well i feel dumb now, should probably get my formulae right first

 

[Doc Al]

incorrect signs

from conservation of momentum and kinetic energy for elastic impacts we have:
$$m_1(V'_1-V_1)=m_2(V'_2-V_2)$$

Not exactly. The net change in momentum is zero, so:
$$m_1(V'_1-V_1)= -m_2(V'_2-V_2)$$

$$m_1(V'_1+V_1)(V'_1-V_1)=m_2(V'_2+V_2)(V'_2-V_2)$$

Again, your signs are incorrect. If the collision is elastic (certainly not the case for the bird hitting the plane!) then KE is conserved, so:
$$m_1V'_1^2 + m_2V'_2^2 = m_1V_1^2 + m_2V_2^2$$