Levers

Question 1

What are levers

Answer 1

A lever is a rigid structure or bar that can move about a pivot.
To move the weight of the lever, a force must be applied.
The levers rotate around a series of joints. The force is provided
by the muscles attached to the bone
The resistance comes from body weight and any implement used for sport

Question 2

Define load, effort, fulcrum, effort arm and load arm

Answer 2

Load - The weight or resistance of the lever arm and anything that is attached to it
Effort - The force of muscle contraction applied to move the lever
Fulcrum - The pivot or fixed point about which the lever moves
Effort arm - The perpendicular distance between the effort and the fulcrum
Load arm - The perpendicular distance between the load and the fulcrum

Question 3

First class lever

Answer 3

This is a lever where the Fulcrum (pivot) occurs between the
effort and load
Sometimes mechanical advantage if fulcrum is closer to load than effort
E.g. F - Neck joint, L - Weight of head / football, E - Muscles in neck contracting

Question 4

Second class lever

Answer 4

This lever occurs when the load is between the effort and the
fulcrum
Always a mechanical advantage as Load closer to fulcrum always
E.g. F - Ball of foot, L - Weight of body and gravity, E - Soleus

Question 5

Third class lever

Answer 5

This lever occurs when the effort is between the load and the
fulcrum
Never a mechanical advantage as Load never closer to fulcrum
E.g. F - Elbow, L - The weight, E - Bicep brachii

Question 6

What is a mechanical advantage

Answer 6

The relative efficiency of each of the lever systems is called the
‘mechanical advantage’.
Mechanical advantage means that the lever allows you to
move a large output load with a smaller effort. (= load/effort)