9.2 what are the types of forces?

• definition of contact forces?

  Forces acting between two objects that are in physical contact with each other , e.g friction and elastic force
• definition of contact force , Forces acting between objects that are in with each other

  forces acting between two objects that are in physical contact with each other
• Friction other way to say it?

  Frictional force
• definition of friction ?

  the force that opposes motion between two surfaces in contact
• What does friction allow us to do?

  hold things without dropping them
• What nuisance does friction cause?

  Wear and tear ( e.g. ball shoes ) , heat is produced ( rubbing hands )
• is elastic force a contact or non contact force?

  Contact force
• Is friction a contact or non contact force ?

  Contact force
• (Elastic force) when stretched or compressed, the in shape

  When stretched or compressed, resists the change in shape
• what is the definition of elastic force?

  force acting on a stretched or compressed elastic object to return to its original shape
• ( rock climbing ) climbers use to which and improves their grip

  Climbers use chalk to absorb moisture which increases friction and improves their grip
• (Rock climbing) their shoes are made out of special rubber to

  their shoes are made out of special rubber to increase friction
• ( rock climbing ) climbing ropes can and exert force , this the felt by the climber when he falls

  Climbing ropes can stretch and exert elastic force , this reduces the impact felt by the climber when he falls
• definition of non contact force?

  forces acting between two objects that are not touching each other e.g magnetic and gravitational force
• definition of Gravitational force?

  A force that attracts two objects towards each other
• GF ( gravitational force ) when a planet exerts gravitational force on an object and pulls it towards its centre , what does the object have?

  Weight
• definition of magnetic force ?

  force exerted between a magnet and another magnetic material e.g. iron/ steel
• What does magnetic force also exist in?

  Between two magnets
• Unlike poles of magnets do what ? , what attraction or repulsion ?

  Pull together , magnetic force of attraction
• like poles of magnets do what? what attraction or repulsion ?

  repel/ push apart, due to magnetic force of repulsion
• VERY IMP , can magnetic materials repel? Can put into answer?

  cannot repel , no VERY IMP, only magnets/ magnetized objects csn be put into ans