ROTATIONAL MOTION

How many suspension points are needed to accurately determine the CG of an irregular object?

• One
• Two or more
• Three only
• Four

In Fig. 6.25, why does the vertical line through suspension point A pass through the CG?

• It is a random alignment
• Due to air pressure
• Because the material is heavy at the bottom
• Because the body aligns itself so that CG is directly below the support

What is the key difference between centre of mass and centre of gravity?

• They are always the same
• Centre of mass is heavier
• Centre of mass depends on mass distribution; centre of gravity depends on both mass and gravity
• Centre of gravity has no mass

Why does the centre of gravity not coincide with the centre of mass in very large bodies?

• Mass is unevenly distributed
• The body rotates
• Gravitational acceleration varies across the body
• Air resistance affects it

What is the primary reason the centre of gravity coincides with the centre of mass in small bodies?

• The body is symmetric
• The mass is negligible
• The body is in space
• The gravitational field is uniform across the body