P6 Forces (Concept Map)
Primary 6 Science — Concept Map
Created by Miss Clarissa Ng · www.clartutors.com
Forces
a push, pull or lift — cannot be seen, but its effects can be felt
two types
Contact forcesobjects in physical contact
Non-contact forcesact from a distance
examples
Frictional forceopposes motion
Elastic spring forcestretched / compressed
Magnetic forceattraction & repulsion
Gravitational forcepull between masses
motion changes when
Balanced forcesequal & opposite → no change
Unbalanced forceslarger force wins → motion changes
what a force can do
Move or stopmoves a stationary object, or stops a moving one
Change motionspeeds it up, slows it down, or changes its direction
Change shapechanges the shape and size of an object
friction: help and harm
Gripfriction gives the grip needed for walking and for holding tools
Wear and tearit also wears things out — shoe soles, machine parts
What changes itmore mass · a rougher surface · no lubricants, rollers or wheels — each increases friction
Not surface areathe amount of friction does NOT depend on the surface area in contact
moving through air and water
Resistanceair resistance opposes motion through air; water resistance does the same in water
Surface areathe greater the surface area, the greater the resistance, so the slower the movement
Streamlinedstreamlined shapes reduce resistance and let objects move faster
Water resistancethe same as air resistance, but in water — it also opposes movement and slows things down
measuring the pull
Weighthow much gravitational force acts on an object — measured in newtons (N)
Massthe amount of matter in an object, in kg or g — independent of gravity
Height does not matteron Earth, the gravitational force on an object is the same however high it is above the ground
More mass, more pullthe greater the mass of an object, the greater the gravitational force acting on it
Mass and weightmass is the amount of matter in an object; weight is the amount of gravitational force acting on it
springs and elasticity
Pull and pushan elastic spring pulls when it is stretched and pushes when it is compressed
The extension graphit always starts at 0: no weights, no extension
Stiffnessfor the same load, a stiffer spring extends less than a less stiff one
More springsmore springs used → greater total spring force