Question 74: Work, Energy and Power & Circular Motion

Question

Two bodies are having kinetic energies in the ratio 16 : 9. If they have same linear momentum, the ratio of their masses respectively is :

Accepted Answer

The kinetic energy of a body of mass $m$ and velocity $v$ is given by $K=\frac{1}{2}mv^2$. Since the bodies have the same linear momentum, we can write:
$$p=mv$$
where $p$ is the linear momentum of the bodies.
Let the masses of the two bodies be $m_1$ and $m_2$ and their kinetic energies be $K_1$ and $K_2$, respectively. Then, we have:
$$\frac{K_1}{K_2}=\frac{16}{9}$$
$$\frac{1}{2}m_1v_1^2\div\frac{1}{2}m_2v_2^2=\frac{16}{9}$$
Since $p=mv$, we have $v_1=\frac{p}{m_1}$ and $v_2=\frac{p}{m_2}$. Substituting these in the above equation, we get:
$$\frac{m_2}{m_1}=\frac{9}{16}$$
Therefore, the ratio of the masses of the two bodies is $\boxed{9:16}$.

Answer

$$3: 4$$

Answer

$$4: 3$$

Answer

$$9: 16$$

Answer

$$16: 9$$

Work, Energy and Power & Circular Motion

Two bodies are having kinetic energies in the ratio 16 : 9. If they have same linear momentum, the ratio of their masses respectively is :

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