WBJEE · Physics · Center of Mass Momentum and Collision
Two identical blocks of ice move in opposite directions with equal speed and collide with cach other. What will be the minimum speed required to make both the blocks melt completely, if the initial temperatures of the blocks were \(-8^{\circ} \mathrm{C}\) each? (Specific heat of ice is \(2100 \mathrm{Jkg}^{-1} \mathrm{K}^{-1}\) and latent heat of fusion of ice is \(3.36 \times 10^{5} \mathrm{Jkg}^{-1}\) )
- A \(840 \mathrm{ms}^{-1}\)
- B \(420 \mathrm{ms}^{-1}\)
- C \(84 m s^{-1}\)
- D \(84 \mathrm{ms}^{-1}\)
Answer & Solution
Correct Answer
(A) \(840 \mathrm{ms}^{-1}\)
Step-by-step Solution
Detailed explanation
Maximum loss in \(K . E=\) Total \(K . E\) energy before collision of two ice blocks \[ K . E_{\max } \text { loss }=\frac{1}{2} m v^{2}+\frac{1}{2} m v^{2}=m v^{2} \] This maximum loss in kinetic energy will be equal to loss in heat to melt two ice block.…
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