Question

Assume acceleration to be uniform.
A bullet losses 1/n of its velocity in passing through a plank. What is the least number of planks requi
stop the bullet ? (Assuming constant retardation)
A car moving along a straight highway with speed 126 kmh 1 is brought to a halt within a distance of 2
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Answer 1

Answer:

I am telling you a short cut formula, where you can directly put the value of n and get the results, see the photo hope you will be able to understand.

Answer 2

Answer:

n^2/2n-1

Explanation:

Since the bullet loses 1/n of its velocity, final velocity = v - v/n = v(n-1)/n

No. of planks = u^2 /(u^2 - v^2)

= u^2/[u^2 - {v(n-1)/n}^2]

= n^2/2n-1