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23 Cards in this Set
- Front
- Back
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What is a force? |
A pull or push |
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Whem do you get gravity or weight do? |
When acts straight downwards |
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When do you get a reaction force from a surface? |
When something usually acts straight upwards |
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When do you get Electrostatic Force between two charged objects? |
The direction depends on the type of the charge LIKE charges REPEL OPPOSITE charges ATTRACTS |
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When do you get thrust, push or pull? |
They are due to an engine or rocket speeding something up |
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When do you get drag, air resistance or friction? |
When something slows down |
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Why do you get lift? |
Due to an aeroplane wing |
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Where do you get tension? |
In a rope or cable |
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Why don't you notice a lot of forces that are acting on an object? |
Because they are balanced out |
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What stops an object with a weight from falling through the surface? |
A reaction force |
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When can you ffel drag |
When an object moves in a fuild - water, air etc - it feels drag in the opposite direction to its motion |
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Why is friction there? |
To slow things down |
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If an object has no force propelling it along, what will happen to it? |
It will slow down and stop - friction is a force that opposes motion |
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What do your need to travel at a steady speed? |
A driving force to counteract the friction |
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What 3 ways does friction occur? |
1. Friction between solid surfaces whichare gripping - static fricition 2. Friction between solid surfaces which are sliding past each other - sliding friction 3. Resistance or 'Drag' from fluids (liquids or gases e.g. air) |
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How can you reduce static friction? |
Put a lubricant like oil or grease between the surfaces, Friction between solids can often cause wear or the two surfaces in contact |
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How can you reduce sliding friction? |
Put a lubricant like oil or grease between the surfaces, Friction between solids can often cause wear or the two surfaces in contact |
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How can you reduce the drag in fluids? |
Keep the object streamlined, like sports cars |
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What can you add to lorries and caravans to make them more streamline? |
Deflectors |
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What can spoil a cars streamlined shape? |
A roof boxes can spoil it and therefore slow them down |
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What does a bigger drag mean? |
The higher the drag, the lower the top speed of the car |
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What can you use to slow down a car drastically? |
A sports car could have a parachute which is about the highest drag as you can get |
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In a fluid,as the speed increases what happens? |
The friction always increases |
