levers Flashcards
pes sugma
Levers definition
are bar like objects that turn around a fixed point, and force are applied to two other points on the object
3 main part of a lever
Resistance, axis and force
how to create arf fro garf
arf down the middle, arf across the middle
Resistance
is the weight to be moved
Axis
is the pivot point
Force
is the application point to move the resistance
1st class+eg
have their axis between the resistance and force eg: see saw
Second class lever + eg
have their axis at the end of the lever with the resistance between the axis and the force, eg: wheelbarrow
Third class levers+ eg
have their axis at the end of the lever with the force in between the axis and resistance eg carrying a load on a shovel
force arm
is the distance from the force to the axis of the lever
resistance arn
distance from the resistance to the axis of the lever
Input force
is the force exerted on the lever
output force
is the force (resistance) exerted by the lever
How to increase application of force/strength
make the force arm longer than the resistance arm
how to increase speed
make the force arm shorter than the resistance arm
Levers in the human body
few examples of first and second class, most levers in the body are 3rd class
Why are 3rd class levers the most common
as we are mechanically built for speed and and 3rd class levers mean their is a large resistance arm
3 factors affecting use of levers
length
inertia
force
Length
The longer a lever, the greater the velocity at the end of the leaver
Inertia
The longer/heavier a lever, the harder it is to rotate
force
the amount of force an athlete can generate via their muscles determines what length of lever they should use
