Question

A bullet

of 10 g strikes a sand-bag at a speed of 103 m/s and gets embedded after travelling 5 cm.

Calculate

(i) the resistive force exerted by the sand on the bullet

(ii) the time taken by the bullet to come to rest.​

Answer 1

Answer:

i)mass of bullet is 10g=1/100 kg

it is fired with speed 103m/s which is u(initial speed)

its gets embedded and stops hence v=0

the distance it travelled is 5cm=1/20m which is S

using 3rd equation of motion

2aS=v²-u²

2a1/20=0-(103)²

a/10=-(103)²

a=-10(103)²  negative sign shows that is decelerated

now we know that F=ma

F=1/100×10(103)²

F=(103)²/10

F=1060.9N

hence the force by which the bullet resisited and stopped is 1060.9N