Levers

Question 1

2 examples of a first class lever

Answer 1

–The movement of head and neck during flexion and extension
– extension of elbow

Question 2

Example of second class lever

Answer 2

Plantar flexion of ankle

Question 3

Examples of 3rd class levers

Answer 3

Hip, knee and elbow flexion

Question 4

Define force arm

Answer 4

The length of line between where fulcrum and effort are labelled

Question 5

Define resistance arm

Answer 5

The length of line between where the fulcrum and resistance is labelled

Question 6

Define mechanical advantage

Answer 6

Where force arm is greater than resistance arm

Question 7

Define mechanical disadvantage

Answer 7

Where the resistance arm is longer than the force arm

Question 8

What is the mechanical advantage for the second class lever
(Plantarflexion of ankle)

Answer 8

–Can generate much larger forces
–Has to lift whole body

Question 9

What is the mechanical disadvantage for the second class lever

Answer 9

Slow, with limited range of movement

Question 10

What is the mechanical advantage for the 1st and 3rd class lever
(1st, extension at elbow–3rd flexion at elbow)

Answer 10

Large range of movement and any resistance can be moved quickly

Question 11

What is mechanical disadvantage of 1st and 3rd class lever

Answer 11

Cannot apply as much force to move an object