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Question
A bullet hits a block kept at rest on a smooth horizontal surface and gets embedded into it. Which of the following does not change?
Options
linear momentum of the block
kinetic energy of the block
gravitational potential energy of the block
temperature of the block.
Solution
gravitational potential energy of the block
When the block kept at rest is hit by a bullet, the block acquires certain velocity by the conservation of linear momentum.
Therefore, the linear momentum and the kinetic energy of the block change.
As some of the kinetic energy carried by the bullet transforms into heat energy, its temperature also changes.
However, the gravitational potential energy of the block does not change, as the height of the block does not change in this process.
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