What are Input and Output Forces? The input and output forces are the two types of forces always involved when any machine is used to do work. In order for the machine to exert force on the load, there needs to be someone or something exerting force on the machine. For example, unless you are pedaling your bicycle, it will not move, or unless you are pushing down on a car jack, the jack will not push up on the car. The amount of force that someone or something exerts on the machine is called the input force, and the amount of force that the machine exerts on the load is called the output force. They are both measured in Newtons. You can also call the input force the effort force, and the output force the load force.
Levers On a lever, the arm on which the input force is being exerted is called the effort arm, it goes from the fulcrum to the effort, and the arm on which the output force is being exerted on the load is called the load arm, it goes from the fulcrum to the load. The location of the effort and load arms vary based on the class of lever:
On a first class lever, the load arm is on one side of the fulcrum, and the effort arm is on the other side. The input force will always be exerted in the opposite direction as the output force.
On a second class lever, the effort arm stretches from the fulcrum to the effort on the other end, and the load arm stretches from the fulcrum to the load, in between the fulcrum and the effort. The input and output forces will be exerted in the same direction.
On a third class lever, the load arm stretches from the fulcrum to the load on the other end, and the effort arm stretches from the fulcrum to the effort, in between the fulcrum and load. The input and output forces will be exerted in the same direction.
Inclined PlanesOn an inclined plane, the output force is the amount of force that would be needed to lift the load straight up, or in other words, how much the object weighs in Newtons. The input force is how much force someone or something has to exert on the load to move it up the inclined plane. For example, if you exert 52 N onto a box to push it up a ramp, and the box weighs 125 N, then the output force is 125 N, and the input force is 52 N.
PulleysOn a fixed pulley, movable pulley, or pulley system, the input force is how much force is used to pull the support rope to lift the load, and the output force is the amount of force that would be needed to lift the load straight up, or in other words, how much the object weighs in Newtons.
Wheels and AxlesA wheel and axle is made up of two parts, a thin shaft (the axle), and a larger disk (the wheel) the input force can be applied to either the wheel or axle, with the output force being produced by the opposite section.
What are Input and Output Forces?
The input and output forces are the two types of forces always involved when any machine is used to do work. In order for the machine to exert force on the load, there needs to be someone or something exerting force on the machine. For example, unless you are pedaling your bicycle, it will not move, or unless you are pushing down on a car jack, the jack will not push up on the car. The amount of force that someone or something exerts on the machine is called the input force, and the amount of force that the machine exerts on the load is called the output force. They are both measured in Newtons. You can also call the input force the effort force, and the output force the load force.
Levers
On a lever, the arm on which the input force is being exerted is called the effort arm, it goes from the fulcrum to the effort, and the arm on which the output force is being exerted on the load is called the load arm, it goes from the fulcrum to the load. The location of the effort and load arms vary based on the class of lever:
On a first class lever, the load arm is on one side of the fulcrum, and the effort arm is on the other side. The input force will always be exerted in the opposite direction as the output force.
On a second class lever, the effort arm stretches from the fulcrum to the effort on the other end, and the load arm stretches from the fulcrum to the load, in between the fulcrum and the effort. The input and output forces will be exerted in the same direction.
On a third class lever, the load arm stretches from the fulcrum to the load on the other end, and the effort arm stretches from the fulcrum to the effort, in between the fulcrum and load. The input and output forces will be exerted in the same direction.
Inclined PlanesOn an inclined plane, the output force is the amount of force that would be needed to lift the load straight up, or in other words, how much the object weighs in Newtons. The input force is how much force someone or something has to exert on the load to move it up the inclined plane. For example, if you exert 52 N onto a box to push it up a ramp, and the box weighs 125 N, then the output force is 125 N, and the input force is 52 N.
Wheels and AxlesA wheel and axle is made up of two parts, a thin shaft (the axle), and a larger disk (the wheel) the input force can be applied to either the wheel or axle, with the output force being produced by the opposite section.