Question

Hola ! ❤

Class - 9

Sub - Physics

Question ;

A bullet of mass 20 gram moving with a speed of 120 m/s hits a thick muddy wall and penetrates into it. It takes 0.03 second to stop in the wall. Find

(a) the acceleration of the bullet in the wall

(b) the force exerted by the wall on the bullet ,


(c) the force exerted by the bullet on the wall

(d) the distance covered by the bullet in the wall.


Answer fast...


Thanks !

Answer 1

I hope you understand my answer......

Answer 2

$\huge{\mathcal{\underline{Answer:}}}$

$<b><i>Given :$

A bullet of mass 20 g moving with a speed of 120 m/s hits a thick muddy wall and penetrates into it. It takes 0.03 second to stop in the wall.

Now,

___________________________

(A) The velocity of the bullet as it hits the wall is u = 120m/s . The velocity after 0.03 s is v = 0.

So, using ;

v = u + at

=> 0 = 120 m/s + a ( 0.03s)

=> a = -120/0.03 m/s²

=> a = -4000 m/s² .

___________________________

(B) The force exerted by the wall on the bullet is

F = ma

=> F = (20g) (-4000 m/s²)

=> F = ( 20/1000 kg ) ( -4000 m/s²)

=> F = -80 N.

The negative sign shows that the force by the wall on the bullet is in the direction opposite to that of the velocity.

___________________________

(C) From Newton's third law , the force exerted by the bullet on the wall is also 80 N, in the direction of the velocity.

___________________________

(D) The distance covered by the bullet in the wall.

s = ut + 1/2 at²

=> ( 120 × 0.03 ) + 1/2( -4000)(0.0009)

=> 3.6 - 1.8 m

=> 1.8 m

___________________________

Thanks for the question !