a bullet flying hirizontally can pierce 9 blocks of same thickness losing 75% of its total kinetic energy. the additonal number of blocks required to just arrest the bullet is:
Dear Ram Sai Charan,
Ans:- Let the initial velocity is U the final velocity is V Then from the given relation we have V²=0.75U²
Let the retardation for each block is =f
then V²=U² - 2f(9x)
where x=thickness of each plate
Let the total no of block required to stop it from it's initial velocity is n
Hence the excess no of plates required=36-9=27(ans)
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