What is Mechanical Advantage? The mechanical advantage of a machine is the number of times it can multiply the force put into it. It is determined by the ratio of the output force in Newtons, to the input force in Newtons. Therefore, the greater the force that the machine exerts on the load, compared to force you exert on it, the higher the mechanical advantage. Since it is just a ratio between the two forces, there is no specific unit to measure mechanical advantage, it is just a number.
The higher the mechanical advantage of a machine, the less force is required to move the load, although the input force will have to be distributed over a greater distance. That is why a high mechanical advantage does not mean that less work is being done, in fact, the amount of work you put into a machine is always more than the useful work it does, because there is always friction that wastes energy. For example, if you push a box up an inclined plane, the box will still reach the same height as if you were to carry it straight up, but you push it with less force because it would travel a longer distance.
Mechanical Advantage of or less than 1 Some machines have a mechanical advantage that is roughly 1, but it is really hard to get a mechanical advantage of exactly 1 due to friction. These types of machines simply change the direction of the input force so that the output force is going in the opposite direction. Examples include a fixed pulley and a first class lever with its fulcrum in the center.
Also, some machines require us to exert a greater input force than the the output force, thus making it harder on us. These machines have a mechanical advantage of less than one because the input force is greater than the output force. Why would we use these machines? Well, the output force is exerted over a greater distance with more speed. This is useful in machines like a baseball bat because the batter can move one end of the bat slightly, and the other end will move a larger distance at a high speed, thus hitting the ball faster. An example includes a third class lever.
Basic ExampleA person has to lift a 50N box to a height of 2m. He uses an inclined plane and has to exert only about 25N of force on the box. The only catch, he has to exert that force over a longer distance. Because he is pushing with roughly half the force that the box weighs, he has to push it for about twice the distance. Therefore, the top of the ramp is 4m long. Video
What is Mechanical Advantage?
The mechanical advantage of a machine is the number of times it can multiply the force put into it. It is determined by the ratio of the output force in Newtons, to the input force in Newtons. Therefore, the greater the force that the machine exerts on the load, compared to force you exert on it, the higher the mechanical advantage. Since it is just a ratio between the two forces, there is no specific unit to measure mechanical advantage, it is just a number.
The higher the mechanical advantage of a machine, the less force is required to move the load, although the input force will have to be distributed over a greater distance. That is why a high mechanical advantage does not mean that less work is being done, in fact, the amount of work you put into a machine is always more than the useful work it does, because there is always friction that wastes energy. For example, if you push a box up an inclined plane, the box will still reach the same height as if you were to carry it straight up, but you push it with less force because it would travel a longer distance.
Mechanical Advantage of or less than 1
Some machines have a mechanical advantage that is roughly 1, but it is really hard to get a mechanical advantage of exactly 1 due to friction. These types of machines simply change the direction of the input force so that the output force is going in the opposite direction. Examples include a fixed pulley and a first class lever with its fulcrum in the center.
Basic ExampleA person has to lift a 50N box to a height of 2m. He uses an inclined plane and has to exert only about 25N of force on the box. The only catch, he has to exert that force over a longer distance. Because he is pushing with roughly half the force that the box weighs, he has to push it for about twice the distance. Therefore, the top of the ramp is 4m long.
Video