Question

The mass of two bodies are 1 Kg and 2 Kg respectively and their kinetic energies are 8 J and 9 J respectively. The ratio of their moments is given by:

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

Answer 1

The correct option is B 2 : 3

Given that,

Mass of first body $m_1=1$kg

Mass of second body $m_2=2$ kg

Kinetic energy of first body

$\frac{1}{2}{m}_1{v}_1^2=8$

$v_1^2=16$

$v_1=4$

Kinetic energy of second body

$\frac{1}{2}{m}_2{v}_2^2=9$

$v_2^2=\frac{18}{2}$

$v_2=3$

Now, the ratio of moments

$\frac{m_1{v}_1}{m_2{v}_2}=\frac{1\times 4}{2\times 3}$

$\frac{m_1{v}_1}{m_2{v}_2}=\frac{2}{3}$

Hence, the ratio of moments is 2:3