Changes

[[Gear]]s are circular disks with 'teeth' that lock together with other gears [[gear]]s to change the force how quickly they are being turned withspin.

| style="height:20px; width:400px; text-align:center;" |The force [[speed]] can be made bigger by turning the larger gear. The small gear will turn more quickly.|} ==Key Stage 3=====Meaning===[[Gear]]s are circular disks with 'teeth' that can act to increase the [[speed]] or the [[Moment|moment of a force]]. ===About Gears===: A small [[gear]] turning a large [[gear]] acts to decrease the [[speed]] and increase the [[moment]].: A large [[gear]] turning a small [[gear]] acts to increase the [[speed]] and decrease the [[moment]]. ==Key Stage 4=====Meaning===[[Gear]]s are circular disks with 'teeth' that can act to increase the [[speed]] or the [[Moment|moment of a force]]. ===About Gears===: The multiplying effect of [[gear]]s can be found by the [[ratio]] of the [[radius|radii]] or the number of 'teeth'. : A [[gear]] with few teeth turning a [[gear]] with many teeth acts to decrease the [[speed]] and increase the [[moment]].: A [[gear]] with many teeth turning a [[gear]] few teeth acts to increase the [[speed]] and decrease the [[moment]].: The bigger [[force]] on one [[gear]] is equal in [[magnitude]] to the [[force]] applied to the other [[gear]]. ===Example Calculations==={| class="wikitable"| style="height:20px; width:200px; text-align:center;" |A [[gear]] with [[radius]] 50mm is turned with a [[moment]] of 10Nm. This [[gear]] used to turn a second [[gear]] with a [[radius]] of 20mm. Calculate the [[moment]] of the second [[gear]]. | style="height:20px; width:200px; text-align:center;" |A [[gear]] with 45 teeth is turned with a [[moment]] of 25Nm. This [[gear will ]] used to turn a second [[gear]] with a bigger 63 teeth. Calculate the [[moment]] of the second [[gear]]. | style="height:20px; width:200px; text-align:center;" |A [[gear]] with 144 teeth is turned with a [[moment]] of 72Nm. This [[gear]] used to turn a second [[gear]] with 60 teeth. Calculate the [[moment]] of the second [[gear]]. |-| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities''' Moment = 10N Radius 1 = 50mm = 0.05m Radius 2 = 20mm = 0.02m| style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities''' Moment = 25Nm Teeth Ratio = 45:63 | style="height:20px; width:200px; text-align:left;" |'''1. State the known quantities''' Moment = 70Nm Teeth Ratio = 144:60 |-| style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].'''<math>M = Fd</math> <math> 10 = F \times 0.05</math> <math> F = 200N</math> An equal [[force]] applies to the second [[gear]]. <math> M = F \times d</math> <math> M = 200 \times 0.02</math> <math> M = 4Nm</math> | style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' <math> M = \frac {25}{45} \times 63</math> <math> M = 35Nm</math> | style="height:20px; width:200px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].''' <math> M = \frac {72}{144} \times 60</math> <math> M = 30Nm</math>