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Question
The momentum of a bullet of mass 20 g fired from a gun is 10 kg.m/s. The kinetic energy of this bullet in kJ will be :
Options
5
1.5
2.5
25
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Solution
Mass of the bullet, (m), = 0.02 gm
Momentum of the bullet, (P) = 10 kg.m/s
The relation between momentum, mass and kinetic energy is as follows -
`K.E = 1/2 (P^2/m)`
So ,
`K.E = 1/2 ((10)^2/0.02)` J
= `100/0.04` J
= 2500 J
= 2.5 KJ
Therefore, the answer is - 2.5.
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