Levers - Mechanical Advantage What is Mechanical Advantage? When we think of machines chances are that you imagine something complex like a car or a bike. It might surprise you that something as simple as a wrench or a screwdriver is a machine. A machine is any mechanical system that helps us perform a certain task or accomplish work easier. Some things machines accomplish is to increase the force, increase the distance, or change the direction of the force. A lever, one of the six simple machines, is very efficient when trying to lift a particularly heavy object. To understand how a lever can do that, we have to define mechanical advantage.
Mechanical Advantage is the amount by which a machine can multiply an input force.
Fin= input force or (the force we apply to the machine)
Fout = output force or (the force required to move the object without using the machine)
Lin = length of the effort arm or (the arm the input force is applied to)
Lout = length of the load arm or (the arm that lifts the object)
Fulcrum = The fixed point on the lever
W = weight (W=mg)
The formula for calculating the mechanical advantage of a lever (as with any simple machine) is the output force (in newtons) divided by the input force (in newtons). However you would have to conduct an experiment and measure these forces in order to find the mechanical advantage.In practice, the friction forces when using a lever are very small, so when we calculate the mechanical advantage we can use the formula for the ideal mechanical advantage. A lever is in balance when:
Relation 1 can be re-written as:
But because Fout/Fin is the mechanical advantage it results that for a lever:
Below you can find videos explaining mechanical advantage in depth: Eureka! Video
Levers - Mechanical Advantage
What is Mechanical Advantage?
When we think of machines chances are that you imagine something complex like a car or a bike. It might surprise you that something as simple as a wrench or a screwdriver is a machine. A machine is any mechanical system that helps us perform a certain task or accomplish work easier. Some things machines accomplish is to increase the force, increase the distance, or change the direction of the force. A lever, one of the six simple machines, is very efficient when trying to lift a particularly heavy object. To understand how a lever can do that, we have to define mechanical advantage.
Mechanical Advantage is the amount by which a machine can multiply an input force.
The formula for calculating the mechanical advantage of a lever (as with any simple machine) is the output force (in newtons) divided by the input force (in newtons). However you would have to conduct an experiment and measure these forces in order to find the mechanical advantage.In practice, the friction forces when using a lever are very small, so when we calculate the mechanical advantage we can use the formula for the ideal mechanical advantage.
A lever is in balance when:
Relation 1 can be re-written as:
But because Fout/Fin is the mechanical advantage it results that for a lever:
Below you can find videos explaining mechanical advantage in depth:
Eureka! Video
Khan Academy Video