Perfectly inelastic collision problem, need some help

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SUMMARY

The discussion centers on solving a perfectly inelastic collision problem involving an 8g bullet and a 250g block. The bullet embeds itself in the block, which then falls from a 1m high table and lands 2m away. Using the conservation of momentum equation, m1v1i + m2v2i = (m1+m2)vf, the initial speed of the bullet was calculated to be 143 m/s. The approach involved calculating the time of flight using kinematic equations and subsequently determining the horizontal velocity.

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eadel
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Homework Statement


An 8g bullet is fired into a 250g block that is initially at rest at the edge of a table of height 1m. The bullet remains in the block, and after the impact the block lands 2m from the bottom of the table. Determine the initial speed of the bullet. [To clarify, the block, after getting hit by the bullet, gets knocked off a 1m tall table and lands 2m away from where it started. no friction either.]


Homework Equations


m1v1i + m2v2i = m1v1f + m2v2f
p=mv

The Attempt at a Solution


before the collision, i have...

m1v1i + m2v2i = (m1+m2)vf

plug in the data...

(0.008)vi + 0 = (0.258)vf


and that's where I'm stumped. I tried using delta-y=v0*t + 1/2at^2 to solve for t and then plug into solve for the velocity in the x direction... (v=d/t)... and then using that as my vf to solve for my vi... and even though the answer LOOKED right (143 m/s) i got the strange feeling it was wrong. any suggestions or leads guys?
 
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Hello, eadel, welcome to PF!
eadel said:
I tried using delta-y=v0*t + 1/2at^2 to solve for t and then plug into solve for the velocity in the x direction... (v=d/t)... and then using that as my vf to solve for my vi... and even though the answer LOOKED right (143 m/s) i got the strange feeling it was wrong. any suggestions or leads guys?
No suggestions or leads are required, your method and solution are perfect!:approve:
 
PhanthomJay said:
Hello, eadel, welcome to PF!No suggestions or leads are required, your method and solution are perfect!:approve:

thank you!

and i can't believe i was right lol, i even went as far as erasing everything :'(

oh well, thanks a lot for the verifcation!
 

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