2. WHAT IS LEVER ?
A lever is a rigid bar which is capable of movement about a fixed point called fulcrum.
3. WHAT IS WORK DONE ?
When a force or Effort (E) applied at one point on lever which acts upon another force or wight
(W) acting at second point on lever.
4. Effort Arm: Perpendicular distance from Fulcrum (F) to the effort (E).
Weight Arm: Perpendicular distance from Fulcrum (F) to the weight (W).
Mechanical advantage: Ratio of weight to the effort.
MA = W/E
6. 1ST ORDER LEVER
It is also known as lever of stability.
Fulcrum is in between effort and weight
(E,F,W)
MA obtained when F is nearer to W.
Example in human body: Atlantoaxial joint
Example: Seasaw
7. 2nd ORDER LEVER
It is also known as lever of power
Here weight is in between effort and fulcrum (E,W,F)
MA is always obtained
Example in human body: Heels raise
Example: Scissors
8. 3rd ORDER LEVER
It is also known as lever of velocity
Here Effort is in between fulcrum and weight. (F,E,W)
MA is never obtained.
Maximum found in human body
Example in human body: Contraction of Biceps while
flexion of elbow joint
Example: Sugar tongs
