Question

A bullet fired on a wooden plank with the velocity of 10ms-1 just penetrates through it what would be the velocity of bullet in order to penetrate through 10 such wooden planks

Answer 1

We can apply, the third equation of kinematics here.

For one plank,

Final velocity = 0 m/s

Initial velocity = 10 m/s

Let the distance it penetrates through be d.

Now, also, make an approximation that it just penetrates the plank, so that we have considered that the final velocity is 0.

Now, the retardation offered to the bullet be a.

So,

by third equation.

0-100 = 2a(d)

Therefore,

a = -50/d

Now, since we want our bullet to cross through 10 bullets, the distance will become 10d.

Also, the retardation offered again will be the same that is a

Now, again by the third law

0-v^2 = 2(-50/d)(10d)

v^2 = 1000 m/s

So,

velocity = 10√10 m/s

Thus, the velocity must be 10√10 as the initial velocity so that it just crosses past the 10 planks.

Answer 2

Answer:

10root 10

Explanation:

I hope it help to u bye