NEET-XII-Physics
25: Calorimetry
- #10A bullet of mass 20 g enters into a fixed wooden block with a speed of 40 m s-1 and stops in it. Find the change in internal energy during the process.Ans : Given:
Mass of bullet, m = 20g = 0.02 kg
Initial velocity of the bullet, u = 40 m/s
Final velocity of the bullet = 0 m/s
Initial kinetic energy of the bullet = `` \frac{1}{2}m{u}^{2}=\frac{1}{2}\times 0.02\times 40\times 40=16\,\mathrm{\,J\,}``
Final kinetic energy of the bullet = 0
Change in energy of the bullet = 16 J
It is given that the bullet enters the block and stops inside it. The total change in its kinetic energy is responsible for the change in the internal energy of the block.
∴ Change in internal energy of the block = Change in energy of the bullet = 16 J
Page No 47: