Upload
maude-lucas
View
217
Download
0
Tags:
Embed Size (px)
Citation preview
Parts of a lever
Within the lever are three components that we need to understand -
•Fulcrum or Pivot - the point about which the lever rotates
•Load or Resistance - the force applied by the lever system. Load to be moved (which includes lever itself)
•Effort or Force - the force applied by the user of the lever system – the force which causes movement
There are three classes of levers
The class of lever is dictated by the arrangement of the 3 components:
Force Arm & Resistance Arm• The distance from the fulcrum (pivot) to the point of
force (effort) is called the FORCE ARM
• The distance from the fulcrum (pivot) to the point of resistance is called the RESISTANCE ARM
Lever characteristics
Long resistance arm: speed and range of movement
Short resistance arm: force
FUNCTIONS OF LEVERSAll levers have 2 functions:
• They either:
1. Increase the speed at which an object can move with a given effort.E.g. driver as opposed to an iron in golf
2. Increase the resistance that can be moved with a given effortE.g. Wheelbarrow – can lift a big weight that would not be able to lift alone
Mechanical advantage
• If Resistance arm is longer, lever is better for force
• If Resistance arm is shorter, lever is better for speed
• In 2nd class levers resistance arm is always longer, therefore 2nd class levers are better for strength or force
• In 3rd class levers force arm is always longer, therefore 3rd class levers are better for speed
So… what happens when a golfer uses different clubs?
• The longer the lever the greater the speed.
• What about control?
• Which is easier to control and hit straight – an iron or a driver?
Question
• In badminton, why is it easier to teach children to hit the shuttle with a shorter racquet?