Machines in the body Flashcards
Define the term Mechanical Advantage?
The factor by which a machine multiplies the force or torque put into it to overcome a resistance force.
Give 4 advantages of simple machines?
Can change the direction of force.
Applying the force may be easier.
Can give a mechanical advantage.
Can magnify the force.
What is the equation in finding the mechanical advantage of a machine?
Mechanical Advantage = Resistance force/Effort Force.
Define the term Wheel and Axle?
Consists of a wheel attached to a central axle about which it revolves.
Give an anatomical example of a wheel and axle?
A cross section of the spinal column, the small muscles act on the ‘axle’ that is the spinal column.
What is a Pulley?
A pulley is a surface with a chain or rope going around it.
What are the 2 types of pulleys?
Fixed.
Movable.
Define a fixed pulley?
Pulley is fastened into position.
Changes the direction of force.
Does not magnify the force.
Define a moveable pulley?
Pulley is fastened to the load.
Load is shared between both ends of the line.
Only half the force is needed to lift the load.
How do you calculate the mechanical advantage of a pulley?
Count the number of lines supporting the load.
Give an anatomical example of a fixed pulley?
The patella working over the knee joint with the patella in place, this facilitates greater mechanical advantage.
Define a force couple?
The interaction of 2 or more muscles acting in different linear directions but producing a torque in the same rotary direction.
Give an anatomical example of a force couple?
The oblique abdominal muscles contracting to rotate the trunk.
