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Chapter 12 Sci
Define Friction | Friction is a force that slows down moving objects and prevents stationary objects from moving. |
What is spring balance? | Spring balance is a device used to measure force. |
On what principle does spring balance work upon? | It uses the principle that the greater the force, the greater is the extension that the force produces in a coiled spring. |
What does friction depend on? | Friction depends on the nature of the surfaces of the objects and the objects' mass. |
Name 5 advantages of friction. | 1)Walking 2)Brakes of cars and bikes 3)Tires of cars and buses 4)Writing on paper 5)Lighting a matchstick on a matchbox |
Name 3 disadvantages of friction | 1)Friction causes wastage of energy 2)Friction wears out the rubbing surfaces 3)Generates heat. |
Name 4 methods of minimizing friction. | 1)Polishing 2)Lubricating (Oil, grease or graphite) 3)Streamlining (To reduce drag by fluids) 4)Wheels and ball bearings |
How can we increase friction(2 points) | 1)Spikes on shoe soles 2)Making the surfaces rough |
What type of force is friction? | Friction is a contact force. |
What is friction due to fluids called? | Friction due to fluids is called drag. |
To reduce drag, the object should have a __________ shape. | Streamlined |
An object is moving from left to right. In what direction will friction act? | Friction will act from right to left. |
Why would a glass fall if you tried to hold it with oily hands? | This is the effect of lubrication. This reduces friction. |