Home Page | Input vs. Output Forces | Mechanical Advantage | Ideal Mechanical Advantage | Mechanical Efficiency | Practice Questions | Challenge Questions | Interactive Quiz | Bibliography In all machines, some of the work you input is converted to thermal energy by friction, meaning the work done by the output force is less than the work done by the input force. The ideal mechanical advantage (IMA) is the number of times a machine is designed to multiply an effort or input force and ignores friction. The formula to calculate IMA is input distance/output distance or Din/Dout. For levers, the input distance, is the distance from the fulcrum to the effort while the output distance is the distance from the fulcrum to the load. For inclined planes, the input distance is the top of the ramp while the output distance is the height of the ramp. When calculating the IMA of a machine, the input distance and the output distance must be measured in the same units. The IMA is never the same as the MA because IMA ignores friction while MA does not. Therefore, it results in two different answers. Like MA, there are no scientific units to measure IMA.
The resistance arm is the output distance. The effort arm is the input distance.
The resistance distance is the output distance. The effort distance is the input distance.
Example: If a hammer moves 10 cm and the nail moves 5 cm, then the IMA is 2. IMA = Din/Dout IMA = 10 cm/5 cm IMA = 2 Friction: A machine’s ideal mechanical advantage is always higher than its mechanical advantage. This is because mechanical advantage takes friction into account which requires you to exert more force on the machine to move the load. Friction is a force resisting the motion between two contacting surfaces. It changes some of the energy you input to become thermal energy. Friction occurs on all parts of a machine that rub together, such as a load moving along an inclined plane, the rope moving along a wheel in a pulley as well as the fulcrum of a lever. The more surface area that rubs against each other, the more friction the machine has. A machine that doesn't have any friction would have its IMA equal to its MA. An inclined plane has a lot of surface area that is rubbing and therefore has more friction, resulting in its IMA greater than their MA. A levers has little surface area that is rubbing and therefore has very little friction, resulting in its IMA and MA to be almost equal. Video Explaining Ideal Mechanical Advantage (3 min 49 sec):
Home Page | Input vs. Output Forces | Mechanical Advantage | Ideal Mechanical Advantage | Mechanical Efficiency | Practice Questions | Challenge Questions | Interactive Quiz | Bibliography
In all machines, some of the work you input is converted to thermal energy by friction, meaning the work done by the output force is less than the work done by the input force. The ideal mechanical advantage (IMA) is the number of times a machine is designed to multiply an effort or input force and ignores friction. The formula to calculate IMA is input distance/output distance or Din/Dout. For levers, the input distance, is the distance from the fulcrum to the effort while the output distance is the distance from the fulcrum to the load. For inclined planes, the input distance is the top of the ramp while the output distance is the height of the ramp. When calculating the IMA of a machine, the input distance and the output distance must be measured in the same units. The IMA is never the same as the MA because IMA ignores friction while MA does not. Therefore, it results in two different answers. Like MA, there are no scientific units to measure IMA.
Example: If a hammer moves 10 cm and the nail moves 5 cm, then the IMA is 2.
IMA = Din/Dout
IMA = 10 cm/5 cm
IMA = 2
Friction:
A machine’s ideal mechanical advantage is always higher than its mechanical advantage. This is because mechanical advantage takes friction into account which requires you to exert more force on the machine to move the load. Friction is a force resisting the motion between two contacting surfaces. It changes some of the energy you input to become thermal energy. Friction occurs on all parts of a machine that rub together, such as a load moving along an inclined plane, the rope moving along a wheel in a pulley as well as the fulcrum of a lever. The more surface area that rubs against each other, the more friction the machine has. A machine that doesn't have any friction would have its IMA equal to its MA.
An inclined plane has a lot of surface area that is rubbing and therefore has more friction, resulting in its IMA greater than their MA. A levers has little surface area that is rubbing and therefore has very little friction, resulting in its IMA and MA to be almost equal.
Video Explaining Ideal Mechanical Advantage (3 min 49 sec):
Link to YouTube: youtube.com/watch?v=E59b5DSJRvo
Home Page | Input vs. Output Forces | Mechanical Advantage | Ideal Mechanical Advantage | Mechanical Efficiency | Practice Questions | Challenge Questions | Interactive Quiz | Bibliography