The kinetic energy of a body is increased by 21%. What is increased in the momentum of the body.
A river of salty water is flowing with a velocity of 10 ms–1.
If the density of the water is 1.2 gm/sc. Then the kinetic energy of each cubic
metre of water is
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Solution
Given that,
(a). Increment of kinetic energy =21%
We know that,
Initial kinetic energy is
K.Ei=x
p2i2m=x
pi=√2mx
Final kinetic energy is
K.Ef=x+21100x
p2f2m=1.21x
pf=√1.21x×2m
Now,
=pf−pipi×100
=√1.21x×2m−√x×2m√x(2m)×100
=√2xm(1.21−1)√2xm×100
=(1.1−1)×100
=10%
Hence, the increment in the momentum of the body is 10%