Contact & Non-contact forces
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 External force comes into picture when the body starts moving or comes to rest either by coming in contact with the body or without being in contact.
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 Contact force- force applied by coming in contact with the body
 Example: hitting of cricket ball with bat in game
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 Non-contact force- force applied without coming in contact with body
 Example: coin attracted towards magnet( magnetic force) ball dropped at height attracted towards the earth( gravitational force)