Question

A bag of sand of mass 9.8 kg is suspended by a rope. A bullet of 200 g travelling with speed 10 ms^-1 gets embedded in it, then loss of kinetic energy will be ______.

विकल्प

• 4.9 J

• 9.8 J

• 14.7 J

• 19.6 J

Answer 1

A bag of sand of mass 9.8 kg is suspended by a rope. A bullet of 200 g travelling with speed 10 ms^-1 gets embedded in it, then loss of kinetic energy will be 9.8 J.

Explanation:

As no external force is acting on system so, P_i = P_f

0.2 × 10 = 10 × v ⇒ v = 0.2 m/sec

Loss in K.E. = ${\displaystyle \frac{1}{2}\times \left(0.2\right)\times {10}^2-\frac{1}{2}\times 10{\left(0.2\right)}^2}$

= ${\displaystyle \frac{1}{2}\times 10\times \left(0.2\right)[10-0.2]}$

= 9.8 J