Calculating Average Force of Bullet Impact on Block

AI Thread Summary
The discussion focuses on 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, resulting in a kinetic energy of 12960 J. The work done by the block on the bullet is equal to the kinetic energy lost, which is expressed as W = F * total distance. By applying the conservation of energy principle, the average force is calculated to be 5184 N after resolving the equations correctly. The final answer confirms the relationship between work, force, and distance in this context.
Freaker
Messages
2
Reaction score
0

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
 
Physics news on Phys.org
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
 
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
Back
Top