ROTATIONAL MOTION

Under what condition do the centre of gravity and centre of mass coincide?

• Only in symmetric bodies
• In zero gravity
• In non-uniform gravitational field
• In a uniform gravitational field

What does the equation Σ mᵢrᵢ = 0 imply about the reference point?

• It is arbitrary
• It is the point of suspension
• The reference point is the centre of mass
• It is the geometric center

Why can g be factored out of the summation in the torque equation?

• Because g is zero
• Because g varies with height
• Because g is a scalar
• Because g is constant for all particles in a uniform gravitational field

What happens to the total gravitational torque when calculated about the centre of gravity?

• It equals the weight
• It is maximum
• It is negative
• It is zero

How is the centre of gravity related to rotational equilibrium?

• It increases rotation
• It has no relation
• It is the point where net gravitational torque is zero
• It stops all motion