What is the basic difference between centre of gravity and centroid?

CG is the point where the weight acts; the centroid is the geometric centre of a shape

CG is for areas only; centroid is for bodies only

They are always different points

When do the CG and the centroid coincide?

When the body is homogeneous and gravity is uniform

2081 Baisakh · 2 marks

Centre of gravity versus centroid

Short answer

Centre of gravity is the point where the entire weight of a body acts, depending on mass distribution and gravity. Centroid is the geometric centre of an area or volume, independent of material. They coincide for a homogeneous body in uniform gravity.

Differentiate between centre of gravity (CG) and centroid.

Point	Centre of gravity (CG)	Centroid
Meaning	The point through which the weight of the body acts	The geometric centre of an area, line or volume
Depends on	Mass distribution and gravity	Shape only
Applies to	3-D bodies (solid, with weight)	Plane areas, lines, volumes (geometric figures)
Material	Depends on density of each part	Independent of material
Coincidence	Coincides with the centroid when the body is homogeneous (uniform density) and gravity is uniform	Same as CG for a homogeneous body
Formula	$\bar x = \dfrac{\sum W_ix_i}{\sum W_i}$	$\bar x = \dfrac{\sum A_ix_i}{\sum A_i}$

✓ Answer checked by Claude Opus 5.5 (high effort)

Principal MI of I-section with semicircular hole · Strength of Materials, chapter 2
Centre of gravity method for warehouse · Industrial Engineering and Management, chapter 2
Centre of pressure below centroid proof · Hydro Power, chapter 1
Instantaneous centre versus relative velocity method · Theory of Mechanism and Machine I, chapter 7
Centroidal MOI of plane figure; define centroid · Applied Mechanics, chapter 4

All Strength of Materials chapter 2 questions →

Centre of gravity versus centroid

Related questions