Force PressureA push or a pull on an object is called force. Force changes the speed, state, dimension and direction of an object.
Ha, this is easy. A force changes the object's speed, direction, state or dimension.
An example would be when we pull a curtain and push a trolley.
Slide: 2
When the resultant force acting on the body is 0 then it is known as unbalanced force.
Balanced forces are equal in size and opposite in direction
they are 2 forces , balanced and unbalanced.
Kids, I am able to stand because the gravity is pulling me towards the ground, So, it can be also called GRAVITATIONAL FORCE.
Slide: 3
YES MA'AM
See, now the books fell down. So, there is no physical contact between the books and my hand, It is called NON - CONTACT FORCE.
See, as I am holding the books, there is a physical contact between the books and my hand, so it is called CONTACT FORCE.
Slide: 4
YES MA'AM
when a force acts over a large area of an object, it produces small pressure. But, if the same force acts over a small area of the object, it produce a large presssure.
Slide: 5
Ma'am, I tripped over the books. Ooouuch !! It hurts..
Laura, do you feel your hair being pulled by the computer Screen ?
Yes Ma'am, I do
It is because of ELECTROSTATIC FORCE. Before you came into the room, I was watching computer. So, the computer is the Charged Body and your hair is Uncharged. Hence, it was attracting your hair.
Slide: 6
MECHANICAL FORCE, the force exerted by machines.Eg - Engine of a Car, Closing and Opening of Door
MAGNETIC FORCE, the force exerted by a Magnet or Magnetic substances.Eg - Magnet attracts Iron,
Ma'am pressure = force --------area
Slide: 0
There are two more forces left. We have done it in class 7. Tell me what it is.
It's ok, Darling. It happened because of FRICTIONAL FORCE. It is the force that opposes motion when two or more objects are in contact move in respect to each other.
Notice this students. For holding the books, my muscles are being used too. So, it can be also called MUSCULAR FORCE.