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A bullet moving with a speed 'v' can jus...

A bullet moving with a speed 'v' can just penetrate two planks of equal thickness. Number of such planks that the bullet will penetrate if its speed is doubled, is:

A

8

B

6

C

9

D

4

Text Solution

Verified by Experts

The correct Answer is:
A
Let F be the resistive force of each block.
Ist case: `1/2mv^(2)=F(2x)`
II nd case: `1/2m(2v)^(2)=F(nx)`
Dividing `1/4=2/n`
`n=8`
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