GCSE Questions: Moments and Centre of Gravity
Q5.
(a) The diagram shows a lampshade hanging from the ceiling.
Draw an X on the diagram so that the centre of the X marks the centre of the mass of the lampshade.
(1 mark)
(b) Complete the sentence: A suspended object will come to rest with its centre of mass directly below 
the point of suspension.
(1 mark)
(c) Arrange the sentences below into the correct order to describe how the student can find the centre of mass of a thin sheet of irregularly shaped card.
The sequence starts with sentence D and finishes with sentence E.
| A |
A line is drawn on the card marking the position of the string. |
| B |
The pin is put through one of the holes in the card and held in the boss. |
| C |
This is repeated using the other hole. |
| D |
Two holes are made in the card with each hole near to the edge of the card. |
| E |
The centre of mass is where the lines cross on the card. |
| F |
The weight is tied to the string and then the string is hung from the pin. |
(D)→B→F→A→C→(E)
All four correct for 3 marks;
or any two correct for 2 marks;
or just one correct for 1 mark
(3 marks)
(Total 5 marks)
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Most of the mass of the lamp will be within the body of the lampshade. It would be low along the central line. 
