How Fast Was the Bullet Going Initially?

AI Thread Summary
To determine the initial velocity of the bullet, one must first calculate the velocity of the block and bullet combination using kinematic equations, considering the height of 25 cm. The conservation of linear momentum principle is then applied to find the bullet's initial velocity. The discussion highlights confusion around the appropriate formulas and the relevance of the height in the calculations. Ultimately, the correct approach involves using both kinematic equations for vertical motion and momentum conservation for the collision. Understanding these principles is crucial for accurately solving the problem.
dcangulo
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A 2.0 kg block of wood rests on a tabletop. A 7.0 kg bullet is shot straight up through a hole in the table beneath the block. The bullet lodges in the block, and the block flies 25 cm above the tabletop. How fast was the bullet going initially?

i tried using this formula:
p= [m_{}b/(m_{}w(sin90))]v_{}b

but it doesn't give me the velocity of anything
maybe I am using the wrong the formula for this?
does the 25cm play a part in anything??
 
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Using kinematic equation, find the initial velocity of block and bullet to reach a height 25 cm above table top. Then applying the conservation linear momentum find the velocity of the bullet.
 

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