Solving Momentum Questions: Inelastic Collisions

[Fresko]

Homework Statement

Homework Equations

Mg deltha H

1/2mv^2

p=mv

The Attempt at a Solution

I believe statement to do with the Gravitational energy is correct, considering the equation I listed. I would have to agree with statement 2 since gpe=keHere is what I am thinking, I disagree with the Ke = the same as before collision.

my reason is 1/2mv^2= 0.16j ----- v= sqrt (0.32/71.6ex-3) now if this is correct we can work out the momentum

which i have down as 1.5 x10^-1 using, momentum is conserved we can work out velocity of the pellet which turns out to be 180m/s (I think this could be wrong)

But could I just say that, the collision was inelastic, hence kinetic energy is not conserved, therefore working out velocity from Momentum would be better since momentum is conserved.

 

[jedishrfu]

This is a terribly formatted post can you clean it up a bit and make sure your equations are correct and readable?

 

[Fresko]

done

 

[Fresko]

anyone help?

 

[haruspex]

I disagree with the Ke = the same as before collision.

my reason is 1/2mv^2= 0.16j ----- v= sqrt (0.32/71.6ex-3) now if this is correct we can work out the momentum

which i have down as 1.5 x10^-1 using, momentum is conserved we can work out velocity of the pellet which turns out to be 180m/s (I think this could be wrong)

But could I just say that, the collision was inelastic, hence kinetic energy is not conserved, therefore working out velocity from Momentum would be better since momentum is conserved.

Good answer.

 

[Fresko]

Good answer.

Are you being serious or troll? I can't tell

If you could outline what is actually good and makes sense in my answer would make me more confident.

 

[berkeman]

Are you being serious or troll? I can't tell

If you could outline what is actually good and makes sense in my answer would make me more confident.

haruspex is most definately not a troll -- he is one of our very valued Homework Helpers and Science Advisors.

 

[haruspex]

I was being quite serious . You correctly identified the flaw in the student's reasoning, and that the correct way is to use conservation of momentum.

 

[Fresko]

I was being quite serious . You correctly identified the flaw in the student's reasoning, and that the correct way is to use conservation of momentum.

but doesn't 180m/s seem to big of a value for the velocity.

 

[haruspex]

but doesn't 180m/s seem to big of a value for the velocity.

No, it looks right to me. Remember that the pellet is only 1/90 of the mass of the ball.