Gravitational force is a force that can act at a distance from an object.Gravitational force is the force of attraction between things and the Earth.Gravitational force pulls all things downwards,towards the centre of the earth.The strength of gravitational force is not the same everywhere.It depends on the distance between object and the earth.An object that is very close to Earth has a greater gravitational force acting on it than an object that is farther away from the earth.
Effects of gravitational force
Gravitational force is acting on us and all other objects all the time.It is because of gravitational force that we are able to stand on the ground and not float away.Gravitational force also has many other effects.
All objects on the Earth have weight.Objects have weight because of the gravitational force acting between them and the Earth.The weight of an object is not the same as the mass of the object.
Frictional Force is a force that opposes motion.It is produced when 2 surfaces rub against each other
Since frictional force opposes motion,it always acts in a different direction opposite to the direction of the object.
Effects of frictional force
-Slow down and stop moving objects
-Prevent an object from starting to move
-affect the movement of objects on different surfaces
Friction can cause problems because it causes objects to:
-slow down
-overheat
-wear out
We can reduce friction between surfaces in many ways including the use of:
-Lubricants
We can apply lubricants such as oil or grease on the moving parts of a machine to reduce friction.With less friction,machines can last longer.
-Roller and wheels
Rollers and wheels can also be used to reduce friction.This enables us to move heavy objects with ease.
