Levers

Question 1

First class lever

Answer 1

Effort at the bottom pointing down - fulcrum middle - resistance at the top right

Question 2

First class lever example

Answer 2

Elbow extension e.g. football throw in
Effort - triceps
Fulcrum - elbow joint
Resistance - hand/ ball

Question 3

Second class lever

Answer 3

Fulcrum bottom left - resistance top middle - effort top, pointing up (left)

Question 4

Second class lever example

Answer 4

Plantar flexion while standing, e.g. to jump
Ball of the foot = fulcrum
Body weight = Resistance
Gastrocnemius = effort

Question 5

Third class lever

Answer 5

Resistance top left - effort top pointing up (middle) - fulcrum bottom right

Question 6

Third class lever example

Answer 6

Elbow flexion - bicep curl w a weight
Resistance - weight of hand/ weight
Effort - force of biceps
Fulcrum - elbow joint

Question 7

Mechanical advantage - definition and equation

Answer 7

Measures how efficient it is at moving heavy loads, the benefit to a lever system

Effort arm/resistance arm

Question 8

Effort arm

Answer 8

Distance from fulcrum to effort

Question 9

Resistance arm

Answer 9

Distance from resistance to fulcrum

Question 10

1st class lever mechanical advantage

Answer 10

high OR low, depends on which variable the fulcrum is closer to

Question 11

2nd class lever mechanical advantage + advantage of it

Answer 11

Always high mechanical advantage (effort arm greater than resistance arm)
- can move large loads with a relatively low effort from the muscles

Question 12

3rd class lever mechanical advantage + its advantage/ disadvantages

Answer 12

Low mA - resistance arm longer than effort arm

• requires a large effort to move a small load
• but can move load quickly through a large range of movement