Work Energy And Power Ques 18

18. If the kinetic energy of a particle is increased by $300 \%$, the momentum of the particle will increase by

[2002]

(a) $20 \%$

(b) $200 \%$

(c) $100 \%$

(d) $50 \%$

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Answer:

Correct Answer: 18.(c)

Solution:

  1. (c) New K.E., $E^{\prime}=E+3 E=4 E$

$p=\sqrt{2 m E}$ and $p^{\prime}=\sqrt{2 m E^{\prime}}$

$\frac{p^{\prime}}{p}=\sqrt{\frac{2 m \times 4 E}{2 m E}}=2$

$ \begin{aligned} & \frac{p^{\prime}}{p}-1=2-1 \text{ [on substracting } 1 \text{ in both sides.] } \\ & \frac{p^{\prime}-p}{p} \times 100=(2-1) \times 100=100 \% \end{aligned} $