Question

In a system, two particles of masses \( m_1 = 3 \, \text{kg} \) and \( m_2 = 2 \, \text{kg} \) are placed at a certain distance from each other. The particle of mass \( m_1 \) is moved towards the center of mass of the system through a distance \( 2 \, \text{cm} \). In order to keep the center of mass of the system at the original position, the particle of mass \( m_2 \) should move towards the center of mass by the distance ______ \( \, \text{cm} \).

Answer 1

Correct Answer: 3

1. Center of Mass Movement Definition: The total displacement of the center of mass (\(\Delta X_\text{C.O.M.}\)) must be zero to preserve its position.
2. Center of Mass Condition Application: If \(m_2\) moves \(x\) cm toward the center of mass, the condition is:
\[ \Delta X_\text{C.O.M.} = \frac{m_1 \Delta x_1 + m_2 \Delta x_2}{m_1 + m_2}, \] with \(\Delta x_1 = 2 \, \text{cm}\) representing the movement of \(m_1\) and \(\Delta x_2 = -x \, \text{cm}\) representing the movement of \(m_2\).
3. Setting \(\Delta X_\text{C.O.M.}\) to Zero:
\[ 0 = \frac{3 \times 2 + 2 \times (-x)}{3 + 2}. \] Upon simplification,
\[ 6 - 2x = 0. \] This yields,
\[ x = 3 \, \text{cm}. \]

Answer: \(3 \, \text{cm}\)