Question

a)explain the change in effect of force with area of contact ,with the help of an activity.
b) formulate the result of the above activity with units

Answer 1

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♦ Force and Pressure | NEWTONIAN MECHANICS |

A ) General Activities may include :
  • Hammering a nail into a wooden plank 
  • Using a Syringe 
  • Caterpillar Tracks 
  • Ice Skates 

Analysis of the Shape of the above few objects gives a particular intrinsic view of the following proportionality :
  ♦ Pressure ∝ ( Area of contact )⁻¹

◘ The Activity 1 says :
   •Try hammering a Nail with its head on a Wooden Plank 
   • Its obvious that you'll end up in an undesirable situation with a failure while with its Pointed edge at the Plank, its pretty easy 

◘ A day-to-day experience of your mom while cutting the veggies with a blunt knife can help you much better to understand the concept :
   ♦ " Effect of Force on the Object of Contact depends on the Area of Contact " - This " Effect of Force " is defined as Pressure and is given by :
   • Pressure = [ Thrust ] [ Area ]⁻¹

b ) When Units are considered, the proportionality :
 ♦ Pressure ∝ [ Force Applied ] 
 ♦ Pressure ∝ [ Area of Contact ]⁻¹ 
     can very easily be converted into the above Formula which can further be simplified as :
  ♦ P = F A⁻¹  with units [ Pascal or Pa for Pressure ]
          • [ Newton or N for Thrust or the perpendicular acting force ]
          • [ Sq. Meter or m² for Area of Contact ]

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Hope this helps 

Answer 2

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Force➫ Any interaction that when unopposed will change the motion of an object.

♦ It's SI unit is Newton (N).

♦ It's formula is F = m × a.

♦ It has both magnitude & direction, making it a vector quantity.

♦ It can cause an object with mass to change its velocity to accelerate.

➊❭ Effects 0f Force are:-
▬▬▬▬▬▬▬▬▬▬▬▬▬⤵

❱ It can make a stationary object move or change its position of rest.

♦Ex:- When you kick a stationary Football it will in motion.

❱ It can change the speed of a moving object.

♦Ex:- When goalkeeper applies force to stop the football.

❱ It can change the direction of motion of a moving object.

♦Ex:- When a batsman hits a ball.

❱ It can change the shape or size of an object.

♦Ex:- When you squeeze a sponge.

❷❭ Types 0f Force are:-
▬▬▬▬▬▬▬▬▬▬▬▬▬⤵

❲1❳ Contact Force➫ A force that acts only when it is in contact with an object.

♦Ex:- Pushing a car up a hill.

❱ Types 0f Contact Force:-
▬▬▬▬▬▬▬▬▬▬▬▬▬⤵

❱ Muscular➾ The force which is exerted by the muscle of your body.

♦Ex:- When you lift your School's Bag.

❱ Frictional➾ The force generated by two surfaces that contacts & slide against each other.

♦Ex:- A person sliding down a slide.

❲2❳ Non-Contact Force➫ A force that acts on an object without being in contact with it.

♦Ex:- Leaves falling from a tree.

❱ Types 0f Non-Contact Force:-
▬▬▬▬▬▬▬▬▬▬▬▬▬⤵

❱ Gravitational➾ A force that attracts any two objects with mass.

♦Ex:- Leaves falling from trees.

❱ Magnetic➾ The force that arises due to the motion of charged particle within the magnetic field.

♦Ex:- Iron pin attracted to magnet.

❱ Electrostatic➾ The attraction or repulsion of particles or objects because of their electric charge.

♦Ex:- When you rub a comb in hair.

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Thanks...✊