Soc 20: Levers

Question 1

What is a lever?

Answer 1

Refers to a system of muscles and bones working together to bring about a movement.

Muscles pull on bones and bones create a movement.

Question 2

How does a lever work?

Answer 2

Made up of 4 components:

1. Fulcrum- pivot, point around which lever rotates.
2. Load- force applied by the lever system (resistance).
3. Effort- force applied by user of lever system (muscles).
4. Lever Arm - rigid bar such as bone.

Question 3

What are the 3 types of levers?

Answer 3

First Class - Fulcrum is in the middle.
Second Class - Load is in the middle.
Third Class - Effort is in the middle.

Question 4

Examples of first class levers.

Answer 4

Tricep Dips- Elbow is the fulcrum between the load (bodyweight) and effort applied by tricep.

Nodding Head - Neck joint is fulcrum and sits between load (head) and effort applied by neck muscles.

Question 5

Examples of second class levers.

Answer 5

Calf Raiser- Bodyweight (load) sits between toes and ball of the feet (fulcrum) and gastrocnemius muscles apply effort pulling the heel.

Lifting a Wheelbarrow -

Question 6

Examples of third class levers.

Answer 6

Bicep Curl - Effort applied by bicep which is between fulcrum at elbow joint and the weight in your hands (load).
Using a Spade - Effort applied by foot (gastrocnemius) which is between fulcrum at the handle and the weight of the soil (load).

Question 7

What is a mechanical advantage?

Answer 7

When a large load can be lifted with relatively low amount of effort.
Input < Output
First and second class levers work at a mechanical advantage.

Question 8

What is a mechanical disadvantage?

Answer 8

Happens when effort and load are on same side of the fulcrum but effort sits closer to load. Effort is greater than the load.
Input > Output
Third class levers work at a mechanical disadvantage.