Levers

Question 1

What is a lever?

Answer 1

A simple machine in the body facilitating movements.

Question 2

What is an axis?

Answer 2

An imaginary straight line around which a body or object rotates.

Question 3

What is a fulcrum?

Answer 3

The point around which the lever rotates.

Question 4

What is load?

Answer 4

The force that is applied by the lever system

Question 5

What is effort

Answer 5

The force applied by the user of the lever system.

Question 6

What is first class levers?

Answer 6

In first class levers, the fulcrum sits in the middle, between the load and effort.
Examples are exercises where elbow or knee straightens.
There aren't many first class levers.

Question 7

Second class levers?

Answer 7

The load sits between the fulcrum and effort.
Second class levers are also quite rare.
Example is a calf raise.

Question 8

Third class levers.

Answer 8

The effort is applied between fulcrum and load.
Most levers in the body are 3rd class levers because the effort is applied between the load and fulcrum.

Question 9

Advantage of First class?

Answer 9

Stable.
Strong.
Increasing the length of the lever arm increases the mechanical advantage.

Question 10

Disadvantage of first class?

Answer 10

Slow.

Limited flexibility.

Question 11

Advantages of second class?

Answer 11

Stable.
Strong.
Increasing the length of the lever arm increases the mechanical advantage.

Question 12

Disadvantage of second class?

Answer 12

Slow

Limited flexibility

Question 13

Advantage of third class?

Answer 13

Fast movement
Large range of motion
Increasing the length of the lever arm decreases the mechanical advantage.

Question 14

Disadvantage of 3rd class levers?

Answer 14

The force applied must always exceed the load.