Collision Help Please

[AliDeLaLouisa]

---

Members don't see this ad.

This is from examkrackers #390 based on perfectly inelastic collisions.

If two masses stick together after colliding, what is the final horizontal velocity of the masses.

I tried to draw it the best I could the diagram

Anyways, my equation is : m1v1 + m2v2 = (m1 + m2 ) v horizontal

the answer is 7 m/s to the left. My calculations are a little off..Is the angle included in this calculation or am I just making this too much?

 

[knightstale4]

Since we are looking for horizontal velocity, we must only consider momentum in the x-direction. Therefore, the angles do matter. In my equations, I am going to assume right is positive.

m1vi1 + m2vi2 = (m1+m2 )vfx
5*10*cos(60) - (20*10) = (5+20)vfx
25-200 = 25vfx
-175 = 25vfx
-7 m/s = vfx
Therefore, both objects will stick together and travel to the left after the inelastic collision.

Hope this helps 🙂

 

[AliDeLaLouisa]

Since we are looking for horizontal velocity, we must only consider momentum in the x-direction. Therefore, the angles do matter. In my equations, I am going to assume right is positive.

m1vi1 + m2vi2 = (m1+m2 )vfx
5*10*cos(60) - (20*10) = (5+20)vfx
25-200 = 25vfx
-175 = 25vfx
-7 m/s = vfx
Therefore, both objects will stick together and travel to the left after the inelastic collision.

Hope this helps 🙂

Thanks!👍