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Forces and pressure (Charlotte) - Coggle Diagram
Forces and pressure (Charlotte)
forces
a push or pull acting on an object
SI unit for forces is Newton (N)
measured by spring balance or dynamometer
effects of forces
change the shape
change the size
change the direction
change the speed
stop a moving object
make a stationary object move
types of forces
contact
a force that results in when two objects are in direct contact with each other
non contact
a force applied to an object that is not in direct contact with it
frictional force
occurs when two objects are in physical contact with each other
acts in the opposite direction and opposes the motion of an object
advantages of friction
daily activities
Friction between the sole of the shoes and the surface of roads allow us to walk, stand or run without slipping or sliding
writing
It helps a pencil to make a mark on papers and enables an eraser to remove the mistake
holding onto objects
It enables iron nails to hold objects together
disadvatages of friction
wear and tear
it causes the shoes, tyres, moving parts in machines or other objects that are used for moving to become worn out
wastage of energy
It produces heat which results in wastage of energy
ways to overcome friction
using oil or grease
lubricating oil or grease makes a surface smoother
hence the object can move across the surface with less friction and will not wear out so quickly
using ball bearings, rollers and wheels
using a cushion of air
gravitational force
acts between two masses without direct contact with each other
affected by two factors
mass of object
larger mass = greater gravitational force
distance between two masses
greater distance = less gravitational force
weight (N) = mass (kg) × gravitational field strength (N/kg)
difference between mass and weight
magnetic force
force of attraction between magnets and magnetic substances
like poles repel and unlike poles attract
application
the magnetic needle in compass indicates the direction to help us navigate through jungles and oceans
pressure
force acting per unit area
SI unit is newton per square metre (N/m²) or pascal (Pa)
pressure in daily lives
Aircrafts are able to fly due to air pressure on the wings
Bullets are fired from a gun using the gas pressure
weight = force
pressure = force over area
