Question

A bullet of mass m=200m/s travelling horizontally with a velocity of v=100m/s penetrates into sand bag upto 50 cm and stops. The average resistance force exerted on the bullet by sand in the bag in KN is
1. 1
2. 2
3. 4
4. 8

Answer 1

The average resistance force exerted on the bullet by the sand bag is 2 kN

Therefore, option (2) is correct.

Explanation:

Given:

Mass of the bullet m = 200 g

Velocity of the bullet u = 100 m/s

The distance travelled by the bullet inside the sand bag s = 50 cm

To find out:

Resistance offered by the plank

Solution:

The final velocity v = 0

By the third equation of motion

$v^2=u^2-2as$

$\implies 0^2=100^2-2a\times 0.5$

$\implies a=-10^4$ m/s²

Therefore, the resistance force

$F=ma$

$\implies F=200\times 10^{-3}\times 10^4$ N

$\implies F=2000$ N

$\implies F=2$ kN

Hope this answer is helpful.

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