Calculating Average Force of Bullet Impact on Block

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Homework Help Overview

The problem involves calculating the average force exerted by a wooden block on a bullet that penetrates it. The bullet has a mass of 18g and a velocity of 1200 m/s, and it penetrates 2.5m into the block.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the relationship between work, energy, and force, referencing the work-energy principle. There is an exploration of the kinetic energy of the bullet and how it relates to the work done on the bullet as it penetrates the block.

Discussion Status

Some participants have provided calculations and attempted to derive the average force, while others have pointed out potential discrepancies in units and the need for clarification on the relationship between energy and force. Multiple interpretations of the problem are being explored.

Contextual Notes

There appears to be confusion regarding the conversion of energy units to force units, as well as the application of the conservation of energy principle in this context.

Freaker
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Homework Statement



A bullet, having a mass of 18g and traveling with a velocity of 1200 m/s strikies a wooden block and pentrates 2.5m. What is the average force exerted by the block on the bullet?


Homework Equations



W= F*total distance
W= .5*m*V2^2 - .5*m*V1^2

The Attempt at a Solution



i got the answer -12960 J
 
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Freaker said:
i got the answer -12960 J

The question is
What is the average force exerted by the block on the bullet

Now your answer is in Joules..Force is in Newtons...so you missed something

Consider the law of conservation of energy;
The Kinetic energy lost by the bullet= Work done in moving the bullet 2.5m into the wooden block...
E_k=W

now you know E_k=\frac{1}{2}mv^2 and you know W=Fs
so you can find F
 
em i still don't think i have the right answer 43200 is that right
 
\frac{1}{2}*\frac{18}{1000}*1200^2=F*2.5
And so
12960=2.5F =>F=5184N
 

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