Soc 20 - Levers

Question 1

What is a ‘lever system’?

Answer 1

A system of muscles and bones working together to produce movement.

Question 2

What are the 4 components of a Lever System?

Answer 2

1) A fulcrum (pivot)
2) A load
3) Effort (muscular)
4) A lever arm

Question 3

What is the fulcrum?

Answer 3

The fulcrum (pivot) is the fixed point (joint) at which the lever rotates.

Question 4

What is the load?

Answer 4

The load is the resistance that is placed on the rigid lever arm structure.

*Essentially the weight of the body part that is moving (plus any extra resistance).

Question 5

What is the effort?

Answer 5

The muscular force that is applied to move the lever.

Question 6

What is the lever arm?

Answer 6

The bone that turns about a pivot.

Question 7

How are levers classified?

Answer 7

Levers are classified according to the position of the fulcrum, load and effort.

This affects how the lever operates.

Question 8

What are the three types of lever?

Answer 8

First class levers
Second class levers
Third class levers

Question 9

What is a first class lever?

Answer 9

The Fulcrum is in the MIDDLE between the effort and the load.

Question 10

What is a second class lever?

Answer 10

The Load is in the MIDDLE between the fulcrum and the effort.

Question 11

What is a third class lever?

Answer 11

The Effort is in the MIDDLE between the fulcrum and the load.

Question 12

What is the way of remembering the classifications of levers?

Answer 12

FLE

First class levers = Fulcrum in the middle
Second class levers = Load in the middle
Third class levers = Effort in the middle

Question 13

What are 3 examples of a first class lever?

Answer 13

1) The neck - when lifting your head to head a football:
- neck muscles provide the effort
- the joint of the neck is the fulcrum (in the middle)
- the weight of the head is the load.

2) Tricep dips
3) Rowing - oarlock = fulcrum, load = water, effort = pulling on oars

Question 14

What is an example of a second class lever?

Answer 14

1) The ankle - pushing off when jumping / starting blocks:
- the balls of the foot acts as the fulcrum
- the weight of the body acts as the load (in the middle),
- the effort comes from the contraction of the gastrocnemius muscle.

Question 15

What are 2 examples of a third class lever?

Answer 15

1) A bicep curl:
- the elbow is the fulcrum
- the bicep contracting is the effort (in the middle)
- the load is the weight of the dumbbell and forearm

2) Kicking a football

Question 16

What are 2 advantages and disadvantages of a first class lever?

Answer 16

Advantages:

• Stable
• Strong

Disadvantages:

• Slow
• Limited Flexibility

Question 17

What are 3 advantages and 2 disadvantages of a second class lever?

Answer 17

Advantages:

• Stable
• Strong
• Mechanical advantage - effort arm longer than the load.

Disadvantages:

• Slow
• Limited Flexibility

Question 18

What are 2 advantages and disadvantages of a third class lever?

Answer 18

Advantages:

• Fast movement
• Large range of movement

Disadvantage:

• Force applied (effort) must exceed the load
• Mechanical disadvantage - load further away from effort, which is closer to the fulcrum.

Question 19

What are the features of a first class lever in rowing? How does this affect a rower’s performance?

Answer 19

• The oarlock acts as the fulcrum in the middle.
• The load is the resistance of the water.
• The effort comes from the muscular pulling force of the rower on the oar.

Link to performance:
-A first class lever provides the rower with a stable and strong anchor from which they can propel through the water, with as little muscular effort as possible.

Question 20

Summaries all the sporting/gym examples of each lever in use:

Answer 20

1st class lever = heading a football / tricep dips / rowing

2nd class lever = pushing off when jumping/starting blocks

3rd class lever = bicep curl / kicking a football