The Student Room Group
Uni students - Complete our survey >>
Uni students - Complete our survey >>
Uni students - Complete our survey >>

M2 Centre of Mass

Where is the centre of mass found on a uniform sphere of hemisphere of radius r, and on a (uniformly filled) semi-circle of radius r? What about on a circular-shaped lamina? And what about a uniformly filled triangle?

Sorry for so many questions but I really have no idea.

I seem to be choosing values that give me the wrong final centre of mass for my combined shape.
The formulas you need are in your formula book.
Reply 2
Avatar for Big-Daddy
Big-Daddy
OP
13
Original post by Mr M
The formulas you need are in your formula book.


I'm with OCR - there aren't any formulae for centre of mass anywhere in the answer book.

This is more the sort of thing I'd like to understand than get a straight-out answer to.
Original post by Big-Daddy
I'm with OCR - there aren't any formulae for centre of mass anywhere in the answer book.

This is more the sort of thing I'd like to understand than get a straight-out answer to.


Seven of them on page 6.

(edited 11 years ago)
CoM.JPG49.0KB
Reply 4
Avatar for Big-Daddy
Big-Daddy
OP
13
Original post by Mr M
Seven of them on page 6.



Thank you for this. I will try and understand them more later.

I know that, if the line downwards from the centre of mass reaches the ground at a point not directly below the object, the object will no longer be in equilibrium and will fall.

However, in this question: http://www.ocr.org.uk/images/63182-question-paper-unit-4729-mechanics-2.pdf (June 2008, Mechanics 2, Q5 part ii) I am not sure what to look for. Can you have a look?
The formulas come from integration. This topic is in M3 for OCR. If you would like an introduction, try this link.
Original post by Big-Daddy
Thank you for this. I will try and understand them more later.

I know that, if the line downwards from the centre of mass reaches the ground at a point not directly below the object, the object will no longer be in equilibrium and will fall.

However, in this question: http://www.ocr.org.uk/images/63182-question-paper-unit-4729-mechanics-2.pdf (June 2008, Mechanics 2, Q5 part ii) I am not sure what to look for. Can you have a look?


The critical point is where the vertical line from the centre of mass passes through the point on the hemisphere that is in contact with the ground.

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you