ROTATIONAL MOTION

How is the centre of mass useful in rocket propulsion analysis?

• It reduces fuel use
• It increases thrust
• To track the motion of the system despite mass ejection
• It stops combustion

What determines the path of the centre of mass of a projectile that explodes mid-flight?

• The force of explosion
• The shape of fragments
• The initial velocity and gravity
• The air resistance alone

What is the dimensional formula of the acceleration of the centre of mass?

• [M¹L¹T⁻²]
• [M⁰L¹T⁻¹]
• [M⁰L¹T⁻²]
• [M¹L²T⁻²]

How does the centre of mass move under a uniform gravitational field?

• With variable acceleration
• With zero acceleration
• With constant acceleration downward
• In a horizontal line

What is the main advantage of using the centre of mass reference frame in collision problems?

• All velocities are zero
• Kinetic energy is zero
• The total momentum in this frame is zero
• Forces vanish