ROTATIONAL MOTION

If a particle has zero mass, what is its contribution to the centre of mass?

• Infinite
• Equal to its position
• Zero
• Undefined

What is the position vector R of the centre of mass in terms of unit vectors?

• R = x i + y j + z k
• R = X i + Y j + Z k
• R = m i + m j + m k
• R = 0

How is the centre of mass affected if a new particle is added to the system?

• It remains unchanged
• It shifts toward the position of the new particle
• It moves away from the new particle
• It becomes zero

For a system of particles in a plane, what determines the Y-coordinate of the centre of mass?

• Arithmetic mean of y-coordinates
• Mass-weighted average of y-coordinates
• Sum of y-coordinates only
• Maximum y-coordinate

What is the value of ∑mi in the denominator of the centre of mass formula?

• Total momentum
• Total force
• Total mass of the system
• Total energy