!!! Levers

Question 1

What are lever systems, functions?

Answer 1

1. Lever systems are the co-ordination of our bones and muscles, primarily to create human movement.
2. Their functions are to:
   - Generate muscular effort to overcome given load
   - Increase the speed of a given movement.

Question 2

What are the components of levers?

Answer 2

The components of levers are:

• Fulcrum.
• Load.
• Effort.
• Effort arm.
• Load arm.

Question 3

What is the fulcrum?

Answer 3

The fulcrum is the pivot or fixed point about which the lever moves.

Question 4

What is the load?

Answer 4

The weight or resistance of the lever arm

and anything that is attached to it.

Question 5

What is the effort?

Answer 5

The effort is the force of muscle contraction applied to move the lever.

Question 6

What is the effort arm?

Answer 6

The effort arm is the distance between the effort and the fulcrum.

Question 7

What is the load arm?

Answer 7

The load arm is the distance between the load and the fulcrum.

Question 8

What is the first class lever? Give example.

Answer 8

The first class lever’s middle feature is the fulcrum. The order of placement is EFL
E.g. elbow extension, a triceps extension
E.g. Extension of the neck when preparing to head a ball

Question 9

What is the second class lever? Give example.

Answer 9

The second class lever's middle feature is the load. The order of placement is ELF
E.g. plantar flexion, a pirouette.

Question 10

What is the third class lever? Give example.

Answer 10

The third class lever's middle feature is the effort. The order of placement is FEL
E.g. elbow flexion, a bicep curl. Almost all levers in the human body are third class.

Question 11

What does the effect of a force within a lever system depend on?

Answer 11

1. The size of the force(effort): greater force(effort) = greater effect
2. The distance from the force(effort) to the fulcrum: the greater the distance the greater the effect.

Question 12

What is the efficiency of the lever system?

Answer 12

1. The greater the distance of the effort or load from the fulcrum, the more significant the effort or load becomes
2. Longer levers generate greater forces, as the load arm becomes longer and therefore can give greater acceleration to projectiles
3. The length of the effort arm and the load arm gives a lever system either a mechanical advantage of mechanical disadvantage
4. 2nd class lever has a mechanical advantage to move a large load with a small effort, such as at the ball of the foot vertically to accelerate an athletes whole weight easily
5. 3rd class lever has a mechanical disadvantage, requiring a large effort to move a small load.