Friction NCERT Science Class 8 Chapter 12 Summary Note
Friction The force that opposes the relative motion between two surfaces in contact, is called friction. Factors affecting friction Weight of object Nature of surfaces in contact More the weight of object, more the friction. More smooth surface experience less friction. Importance of friction Friction helps in stopping object Friction helps to write, walk, Friction helps in all activities Friction produces heat. Harm cause by Friction Sole of shoes wear out. Machine parts get wear out. Friction can be increased by making surfaces rough. ( More rough means more interlocking between surfaces which means more friction ) Friction can be decreased by applying lubricant on surfaces. Friction can be decresed by changing shape of object. Rolling friction The force that oppose motion of rolling object, is rolling friction. Sliding friction The force that oppose moti...
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