Question

NOTE: F.A.R full form is Floor area ratio & FA is Floor Area.

1. Draw a basic F.A.R for each of the following and give an example of where in the body you may find each.

    First class lever:

    Second class lever:

    Third class lever:

2. Which class of levers is designed best for speed and range of motion and which is best for strength?

3. What forces determine amount of torque in a system?
4. A. How much torque needs to be produced to move 60 kg (R) when the RA is 0.30 m and the FA is 0.1 meters?

Answer 1

Basic FAR

Examples

First class lever: Neck extension

Second class lever: Plantar flexion

Third class lever: Elbow Flexion

All second-class levers in the body work at a mechanical advantage because the muscle insertion is always farther from the fulcrum than the load. Second-class levers are levers of strength, but speed and range of motion are sacrificed for that strength.

Torque is the turning effect of a force ; inside the body it caused rotation around a joint .

Torque = Force ( from the muscle ) x Force Arm ( distance from muscle insertion from the joint )

A.

Given RA =0.30m, R =60Kg and FA = 0.10m

By Using F *FA =R*RA

F*0.1m = 60 kg *0.30m

F= 180kg

180kg torque needs to be produced to move 60 kg (R) when the RA is 0.30 m and the FA is 0.1 meters