Question

Two masses of 1g and 9g are moving with equal kinetic energy. The ratio of magnitude of their momentum is

• A. 3 : 1
• B. 1 : 3
• C. 1 : 2
• D. 2 : 1

Hint:

Momentum at same KE is \( p = \sqrt{2mE} \Rightarrow p \propto \sqrt{m} \). So ratio becomes \( \sqrt{m_1/m_2} \).

Answer 1

The Correct Option is B

Kinetic energy: \[ KE = \frac{p^2}{2m} \Rightarrow p = \sqrt{2mKE} \] For same kinetic energy: \[ p \propto \sqrt{m} \Rightarrow \frac{p_1}{p_2} = \sqrt{\frac{m_1}{m_2}} = \sqrt{\frac{1}{9}} = \frac{1}{3} \]