Science Form 2: Chapter 9: Stability
Point of equilibrium = Centre of gravity
The centre of gravity is the point at which the Earth's gravity acts on that object.
The centre of gravity is the point at which the Earth's gravity acts on that object.
- The lower the centre of gravity,the more stable the object.
- The wider the base of an object,the more stable thr object.
A heavier object is more stable than a lighter object of same size & shape.
Concept of stability:
The giraffe stands with its legs spread wide apart to increase its base and lowers its centre of gravity.This makes it more stable.
An object will topple if the vertical line through its centre of gravity falls outside its base area.
PT3 Practise:
1. Ahmad is a driver for a double decker bus.There were only 10 passengers in the bus.Ahmad asked them to sit at the lower part of his bus.Justify his instruction. (3 marks)
- When the passengers sit on lower part of the bus,the weight at the base of the bus increases.This makes thr bus more stable when driving.This lowers the centre of the gravity of the bus.If the passengers sit on thr upper deck,the centre of gravity of bus is raised.As a result,the bus will be less stable.
2. Imagine you are an architect who have been asked to design a 1000 metres twin tower building.Suggest how you can make a stable buildring based on the principle of stability. (4 marks)
- increase the size of base area of the towers to make them more stable
- increase the weight at the base of the towers to lower the centre of gravity
- design the towers in a cone shape so that they have a low centre of gravity
- build a structure that connects the two towers to help increase the size of the base area
- increase the weight at the base of the towers to lower the centre of gravity
- design the towers in a cone shape so that they have a low centre of gravity
- build a structure that connects the two towers to help increase the size of the base area
3. Ridwan's sister wore high heeled shoes for a vacation in Cameron Highlands.When she was walking down the hilly road,she toppled and fell down.Explain why she toppled and fell down and suggest one way to increase your stability when wearing high heeled shoes. (3 marks)
- High heeled shoes have high centre of gravity and narrower.This raises the centre of gravity of Ridwan's sister.When she was walking down the hilly road,the vertical through her centre of gravity falls outside of her base area and makes her unstable.