Force
A push or pull acting on an object
is called a force.
Things do not move by themselves
Everything needs a push or a pull to
make it move.
What is the main force when we are
playing tug of war?
Pull
ØWhat is the main force in wrestling?
Push
·when we applied force the moving ball stopped due to the
push the direction and speed of the ball changed
.
·On pressing the shape and size of the clay changed
·A bowler throws a cricket ball towards the batsman. The bats
man uses force to
change the direction of the ball
.Thus force can change the direction of a moving object
‘
Frictional force is a force which is exerted when two surfaces
come in contact with each other and resists the motion of the object and the
object either slows down or stops moving.
It is the frictional force which stops the cycle when you apply the brake
What happens to the ball when it is
thrown up wards?
It goes up and then comes back to
the ground.
ØWhen objects are thrown upwards, they came down. Why?
Due to gravity of earth.
ØWhy does a fruit from tree falls on the ground and not moves
up in the air?
Due to gravity of earth, the earth
exerts a force called Gravity or gravitational force that pulls everything
towards it.
·Gravity acts on everything all the time. It prevents you from
floating in the air. If
there was no gravity, we would be
floating in the air Who are these people ?
Astronauts
·Why are they floating around and not able to stand straight
like us?
·Astronauts float around in space because there is very
little gravity in space
.
·The farther you get from Earth, the less the gravitational
force is and astronautsare so far from the Earth that the gravity is very less
and thereforein space,astronauts do not walk on the floor like people on Earth
do. They float aroundinside their spacecraft,
ØWhen objects are thrown upwards, they came down. Why?
Due to gravity of earth
ØWhy does a fruit from tree falls on the ground and not moves
up in the air?
Due to gravity of earth.
ØWho discovered gravity?
Isaac Newton
ØWhat is gravity?
Force that pulls objects downwards
towards the centre of the Earth.
Which force was acting when Golu was
playing carom with his sister and
Striking the coins with the striker?
( Frictional force)
·
What is friction?
(The friction is the force exerted
by a surface as an object moves across it or makes an effort to move across it.
The force of
friction allows us to push against the ground, walk, run or move forward. It is
created when two objects come in contact with each other
·Friction is more on a rough surface than a smooth surface
What did you observe?
lid of the jar could not be opened
with the hands with vaseline where as it opened easily with dry hands.
ØWhy did it happen so?
Because friction was less between
the surface of lid and palms in case of hands with vaseline and friction was
more in case of dry hands.
