Question

A bullet travelling horizontally looses 1/20 of its velocity while piercing a wooden plank. Then the number of such planks required to stop the bullet is​

Answer 1

Answer:

ANSWER

Let s be the length of each block.

After piercing it is decelerating so acceleration is negative.

So, the equation of motion:

v

2

=u

2

−2as

⟹

20

2

19

2

u

2

=u

2

−2as

or, 2as=

400

39

u

2

Now let's assume the bullet will pass through n number of blocks. So the net distance traveled by the bullet will be ns and finally, it will come to rest.

So, using the equation of motion:

v

2

=u

2

−2as

⇒ 0=u

2

−2ans

⇒ n=

2as

u

2

Substituting value of 2as, we get:

n=

39

400

=10.3

Hence, a number of planks required is 11.

Explanation:

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Answer 2

Explanation:

used this formula you get answers