Work Energy and Power - Result Question 26

29. Two bodies of masses $m$ and $4 m$ are moving with equal K.E. The ratio of their linear momenta is

[1997]

(a) $4: 1$

(b) $1: 1$

(c) $1: 2$

(d) $1: 4$

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Answer:

Correct Answer: 29. (c)

Solution:

  1. (c) $m_1=m, m_2=4 m$

$K . E_1=K . E_2$

$\frac{1}{2} m_1 v_1^{2}=\frac{1}{2} m_2 v_2^{2} ; \quad \frac{1}{2} m v_1^{2}=\frac{1}{2} 4 m v_2^{2}$

$\frac{v_1}{v_2}=2 \Rightarrow v_1=2 v_2$

Linear momentum of first body

Linear momentum of second body

$=\frac{m_1 v_1}{m_2 v_2}=\frac{m \cdot 2 v_2}{4 m v_2}=\frac{1}{2}$