Types of machine in the body: lever systems

Question 1

What are lever systems used to generate?

Answer 1

Used to generate torques onto the joints and rotate our limbs.

Question 2

Name the 4 main components of levers

Answer 2

1.The lever arm (bones)
2.The fulcrum (A)
3.The force of the muscle (f)
4.The resistance of body weight (r)

Question 3

What is the equation for torque

Answer 3

Torque= force times moment arm

Question 4

What is the equation of mechanical advantage

Answer 4

The length of force arm divided by the length of resistance arm.

Question 5

Describe and give an example of a first class lever

Answer 5

e.g. Nodding head on neck.
Lever-skull
Axis of rotation is the skull joint.
Resistance is the weight of skull.
Force is the posterior neck muscles.

Question 6

Describe and provide an example of a second class lever

Answer 6

E.G. plantar flexion.
Lever is the bones of the foot
Resistance is the weight of the body.
Force is the calf muscles.
2nd class levers always have a mechanical advantage of greater than 1.

Question 7

Describe and provide an example of a third class lever

Answer 7

E.G. Elbow flexion.
Lever-bones of the forearm.
axis of rotation-elbow joint.
Resistance- weight of the forearm.
Force- contraction of the biceps.

Question 8

What are the advantage of third class levers in the body?

Answer 8

Provide a greater range of movement, and a greater velocity.