Week 8 - Torque, Levers and Mechanical Advantage Flashcards
What is torque?
The rotary effect of a force about an axis of rotation
Torque= ?
Moment - (moment arm)
What are examples of torque?
Opening a door , turning on a tap , loosening a nut with a spanner
What is the torque equation? And what units is torque measured in?
Torque = F. Dt
- Force measured in newtons
- distance or moment arm measured in metres
- newton metres (n.m)
Where do torques occur within the human body?
Product of muscle tension (force) and muscle moment arm produces a torque at the joint crossed by the muscle. Maximal at 90 degree angle
What is a lever?
A simple machine consisting of a relatively rigid bar-like body that can be made to rotate about an axis or a fulcrum.
What is a first class lever?
F. A. R.
What is a second class lever?
A. R. F.
What is a third class lever?
A. F. R.
Example of each class lever in the body.
Triceps - 1st
Plantar flexion (calf raises) - 2nd
Biceps at elbow, Patella tendon at knee - 3rd
What is mechanical advantage ?
The ratio of the moment arm of the force arm to the moment arm of the resistance for a given lever.
What equation calculates mechanical advantage?
Mech advantage = moment arm of the force / moment arm of the resistance
> 1 force needed to move is < than resistance
<1 force needed to move is > than resistance
