Initial Speed of 5.5g Bullet Fired into 22.6g Wood Block

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Homework Help Overview

The problem involves a 5.5 g bullet fired into a 22.6 g wood block, which is initially at rest on a 1.5 m tall post. After the collision, the combined system lands 2.5 m from the base of the post. The objective is to determine the initial speed of the bullet.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the need to calculate the time it takes for the block to fall 1.5 m and how to use that to find horizontal velocity. There are questions about starting points and initial attempts to approach the problem.

Discussion Status

Some participants have offered guidance on how to begin the calculations, while others express confusion about the initial steps. There is no explicit consensus on the approach, but multiple lines of reasoning are being explored.

Contextual Notes

Participants are navigating the complexity of the problem, which involves multiple steps and calculations. There is an emphasis on understanding the relationships between the variables involved in the collision and subsequent motion.

Addison
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A 5.5 g bullet is fired into a block of wood with a mass of 22.6g. The wood block is intially at rest on a 1.5m tall post. After the collision, the wood block and bullet land 2.5m from the base of the post. Find the initial speed of the bullet.
 
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watters

I need help starting it! I'm sort of confused. Thanks for your time.
 
Originally posted by Addison
A 5.5 g bullet is fired into a block of wood with a mass of 22.6g. The wood block is intially at rest on a 1.5m tall post. After the collision, the wood block and bullet land 2.5m from the base of the post. Find the initial speed of the bullet.

Ah the great many many many step question.

First find the time it took to fall the 1.5m using this equation

[tex]d = V_it + \frac{1}{2}at^2[/tex]

Since you know the time and the horizontal distance, find the horizontal velocity using this formula

[tex]V = \frac{d}{t}[/tex]

Now that you know the horizontal velocity of the block and and the bullet, you can also find and compare the inertia. Subscript bu will be bullet and bl will be block.

[tex](V_b_u) (m_b_u) = (V_b_u_+_b_l) (m_b_u_+_b_l)[/tex]


I hope I didn't leave anything out.
 
Here is a recent thread dealing with this problem.
 

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