Question

A bulletin of mass 0.05kg is fired from a rifle with a velocity of 800m/s After passing wall of thickness 1m it's velocity reduces to 200m/s find the resistive force of the wall

Answer 1

Answer:-

F = -15000N

Explanation:-

Given:-

• m = 0.05kg
• u = 800 m/s
• v = 200 m/s
• s = 1m

To Find:-

Resistive Force of the wall on bullet

Solution:-

$\boxed{\bold{{v}^{2}-{u}^{2}= 2as}}$

${\rightarrow} \: {200}^{2}-{800}^{2}= 2a (1)$

${\rightarrow} \: 40000- 640000= 2a$

${\rightarrow} \: 40000- 640000= 2a$

${\rightarrow} \: -600000= 2a$

${\rightarrow} \bold{\: a = -300000 m{s}^{-2}}$

F = ma

${\rightarrow} \: F = 0.05 \times -300000$

${\rightarrow}\bold{ \: F = -15000N}$

Answer 2

$\huge{\bold{\underline{\underline{....Answer....}}}}$

$\huge{\bold{\underline{Given:-}}}$

Initial velocity (u) = 800 m/s.

Final velocity (v) = 200 m/s.

Thickness (S) = 1 m.

Mass of the body (M) = 0.05 Kg.

$\huge{\bold{\underline{Explanation:-}}}$

Applying third kinematic equation.

$\large{\bold{v^2 - u^2 = 2as}}$

Substituting the values,

$\large{(200)^2 - (800)^2 = 2 \times 1 \times a}$

$\large{40000 - 640000 = 2 \times a}$

$\large{a = \frac{40000 - 640000}{2}}$

$\large{a = \frac{ - 600000}{2}}$

$\large{a = \frac{ \cancel{ - 600000}}{ \cancel{2}}}$

$\large{a = - 300000}$

$\large{\bold{\boxed{a = - 30 \times 10^4 \: m/s^2}}}$

Applying Newton's second law

$\large{\bold{F = ma}}$

Substituting the values,

$\large{F = 0.05 \times - 30 \times 10^4}$

$\large{F = 5 \times 10^{-2} \times - 30 \times 10^4}$

$\large{F = 5 \times - 30 \times 10^{(4 - 2)}}$

$\large{F = - 150 \times 10^2}$

$\large{F = - 15 \times 10^3}$

$\huge{\boxed{\boxed{F = - 15 \: KN}}}$

So, resistive force has a value of - 15 Kilo Newton's.

The negative sign indicates that force is acting in the opposite direction of the motion of the body.