4596950
Description
Mind Map by Lilac Potato, updated more than 1 year ago
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Created by Lilac Potato
almost 9 years ago
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GCSE AQA Physics 3 Forces
- Moments
- Moment = Force x Distance from
line of action of force to pivot
- Larger force = larger moment
- Same force can exert larger moment
if distance from pivot is greater
- To get max. moment -
need to push at right angle
- To get max. moment -
need to push at right angle
- Total clockwise moments =
Total anticlockwise moments
- Levers use balanced moments
- Increase distance from pivot
at which force is applied
- Less force is needed to
get same moment
- Levers are force
multipliers
- Make it easier to do work
- Make it easier to do work
- Levers are force
multipliers
- Less force is needed to
get same moment
- Increase distance from pivot
at which force is applied
- Levers use balanced moments
- Moment = Force x Distance from
line of action of force to pivot
- Centre of Mass
- Point at which whole
mass is concentrated
- Freely suspended object will swing
until its centre of mass is vertically
below the point of suspension
- Finding the COM
of a flat shape:
- Suspend shape & plumb line
from same point - stop moving
- Draw line along plumb line
- Repeat with shape suspended
from different pivot point
- COM is where 2 lines cross
- COM is where 2 lines cross
- Repeat with shape suspended
from different pivot point
- Draw line along plumb line
- Suspend shape & plumb line
from same point - stop moving
- With symmetrical shape - can
find it using lines of symmetry
- Point at which whole
mass is concentrated
- Stability
- If moments aren't equal
- will be resultant force
- Most stable objects have wide
base & low centre of mass
- Object will tip over if the line of action of the
weight of the object lies outside of the base
of the object - causes a resultant moment
- If moments aren't equal
- will be resultant force
- Pendulum
- Time taken to swing
from one side to other
& back - time period
- Always the same for each
swing of given pendulum
- Time Period = 1 / Frequency
- Longer pendulum - greater time period
- Longer pendulum - greater time period
- Always the same for each
swing of given pendulum
- Time taken to swing
from one side to other
& back - time period
- Hydraulics
- Liquids are virtually
incompressible & can flow
- Force applied to one point
in liquid transmitted to
other points in liquid
- Pressure in a liquid is transmitted
equally in all directions
- Pressure = Force / Cross-sectional area
- Pressure = Force / Cross-sectional area
- Pressure in a liquid is transmitted
equally in all directions
- Force applied to one point
in liquid transmitted to
other points in liquid
- Hydraulic systems - force multipliers
- 2 pistons - 1 with smaller cross-sectional area
- Pressure at both pistons is same
- At 1st piston - pressure exerted
using small force over small area
- Pressure transmitted to 2nd piston -
has larger SA so there is larger force
- Pressure transmitted to 2nd piston -
has larger SA so there is larger force
- At 1st piston - pressure exerted
using small force over small area
- Pressure at both pistons is same
- Used in car braking systems & car jacks
- 2 pistons - 1 with smaller cross-sectional area
- Liquids are virtually
incompressible & can flow
- Circular Motion
- Velocity is speed & direction - object travelling in
circle is constantly changing direction
- Velocity is constantly changing (not speed)
so is accelerating towards centre of circle
- Must be resultant force causing
acceleration - acts towards centre
- Centripetal force
- Faster moving object = bigger CF
- Larger mass = bigger CF
- Smaller radius = bigger CF
- Faster moving object = bigger CF
- Centripetal force
- Must be resultant force causing
acceleration - acts towards centre
- Velocity is constantly changing (not speed)
so is accelerating towards centre of circle
- Velocity is speed & direction - object travelling in
circle is constantly changing direction
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