Question

9. A bullet of 20 g strikes a sand bag at a
speed of 200 m/s and gets embedded
after travelling 2 cm, then the resistive
force exerted by sand on the bullet is​

Answer 1

Answer:-

Given:-

Given, u = 200 m/s, v = 0, s = 0.02 m

and m = 20 g = 20 x 10^-3kg

solve:-

From third equation of motion, v^2 = u^2 + 2 as a

${⇒}a = \frac{ {v}^{2} - {u}^{2} }{2s}$

${⇒} \frac{(0)^{2} - (200) ^{2} }{2 \times 0.02} = - {10}^{ - 6} {frac \: {m}{s^{2} } }$

Negative sign indicates retardation.

Resistive force, F = ma = 20 x 10^-3 x 10^6

 

                                         = 2 x 10^4  N

Therefore:-

2 x 10^4 N