ROTATIONAL MOTION

What is the physical meaning of the position vector ri in the centre of mass formula?

• It represents velocity
• It gives the location of the ith particle in space
• It is the force vector
• It is the acceleration

How is the centre of mass concept applied to rigid bodies?

• By ignoring internal structure
• By treating them as point masses only
• By treating them as systems of closely packed particles
• By assuming zero mass

If two particles have different masses, where is the centre of mass located?

• Exactly midway
• Closer to the lighter particle
• Closer to the heavier particle
• At the origin

What is the general formula for the Z-coordinate of the centre of mass of n particles in space?

• Z = ∑zi
• Z = (∑mi zi)/M
• Z = ∑mi/M
• Z = M/(∑mi zi)

For a system of particles along the x-axis, what does X represent in the centre of mass formula?

• Total displacement
• Distance of centre of mass from origin
• Sum of all positions
• Velocity of system