FORCE & PRESSURE PART 2

qA force that results due to action of muscles is known as MUSCULAR FORCE.

qIt is used to perform different activities;

walking, running, catching and lifting certain objects..

qIt is also used in different hand tools. Such as hammers, knives, saws etc..

qDomesticated animals are also used with different instruments to accomplish a variety of tasks or activities;

i.Buffaloes are used to plough farms for agriculture

ii.Camels, donkeys and horses are used to carry luggage in remote areas.

iii.Horses and buffaloes are used to run carts to carry loads

vA force that acts along the two surfaces  in contact and opposes the motion of one object over another is called the force of friction.

vA force of friction always acts on the objects that are in motion.

vIt is applied at the point of contact of 2 bodies.

vIt arises due to contact between 2 surfaces.

vA ball rolling on the ground gradually slows down and finally comes to rest due to the force of FRICTION.

ØA force that is exerted by a magnet on other magnetic material is called a MAGNETIC FORCE

ØIt is a non-contact force because there is no physical contact between the materials

ØThis force is due to magnetic field developed around the magnet

ØA magnet has 2 poles; NORTH & SOUTH

ØWhen two magnets are brought together, then like poles repel and unlike poles attract.

ØA magnet is made up of:

1) COBALT; 2) NICKEL; 3)IRON  & their alloys.žTake a pair of bar magnets. Place the longer side of one of the magnets over three round shaped pencils or wooden rollers .

žNow bring one end of the other magnet near the end of the magnet placed on the rollers.

ž Make sure that the two magnets do not touch each other.

žObserve what happens.

ž Next, bring the other end of the magnet near the same end of the magnet placed on the rollers.

žWe can conclude that Magnetic force is an example of Non – Contact Force

žA force exerted by a  charged on another charged or uncharged body is known as ELECTROSTATIC FORCE.

žLike magnetic force this also exists without any contact between the two bodies.

žExample;

a.When a comb is rubbed on dry hair, then comb can attract small pieces of papers.

žTake a plastic straw and cut it into nearly two equal pieces.

žSuspend one of the pieces from the edge of a table with the help of a piece of thread.

žNow hold the other piece of straw in your hand and rub its free end with a sheet of paper.

žBring the rubbed end of the straw near the suspended straw.

ž Make sure that the two pieces do not touch each other.

ž Next, rub the free end of the suspended piece of straw with a sheet of paper.

ž Again, bring the piece of straw that was rubbed earlier with paper near the free end of the suspended straw.

ž What do you observe now?

ž 

OK...... THANK U BYE

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