What is Ideal Mechanical Advantage?The ideal mechanical advantage of a machine is its mechanical advantage, not including the work done by the force input force that ends up getting wasted as heat because of friction. In other words, it is what the mechanical advantage of a machine with zero friction would be. The ideal mechanical advantage is determined by the ratio of the distance over which the input force is exerted on the machine, to the distance over which the output force is exerted on the load.
Therefore, the greater the distance over which the input force is exerted on the machine (the input distance), compared to the distance over which the output force is exerted onto the load (the output distance), the greater the ideal mechanical advantage is. The greater the ideal mechanical advantage is, the less force will be required to move the load, although the input force will have to be distributed over a greater distance. Since the ideal mechanical advantage is just a ratio comparing the two distances, there is no specific unit to measure it, just a number. What's the difference between MA and IMA?The main difference between ideal mechanical advantage and mechanical advantage is that the mechanical advantage takes into account the friction that wastes energy as heat in all machines, but the ideal mechanical advantage doesn't. This is because mechanical advantage compares the input and output forces, which vary depending on the amount of friction in the machine, but ideal mechanical advantage compares the distances over which those forces are applied, so it doesn't take into account the amount of friction.
Levers, Inclined Planes, Pulleys, and Wheels and AxlesThe input distance is the distance over which you exert a force on a machine to move a load, and the output distance is the distance you would have to move the load without the machine, how much the load moves.
On a lever, you can calculate the IMA two ways, you can use the ratio of the input distance, the output distance. Or, you could use the ratio of the length of the effort arm, to the length of the load arm. Just be careful that you do not use a ratio comparing the input or output distance and the length of an arm, this would not give you the IMA. This is because the distances traveled can be different to the length of the arms, but they have the same ratio. On an inclined plane, the input distance is the length of the top of the inclined plane because that is the distance the load is pushed, and the output distance is the height of the inclined plane, because that is the height the load reaches.
On a fixed pulley, the ideal mechanical advantage is always one, but the direction of the input and output forces are opposites. On a movable pulley or a pulley system, you find the ideal mechanical advantage by counting the number of support ropes. On a wheel and axle, instead of comparing the input and output distances to find the IMA, you would compare the radius of the axle and the radius of the wheel. If you were applying the input force to the wheel, the IMA would be the ratio of the wheel's radius to the axle's, and it would always be greater than 1. If you were applying the input force to the axle, the IMA would be the ratio of the axle's radius to the wheel's, and it would always be less than 1. For example, when you hold a screwdriver's handle, you would need to exert less force than you would if you held onto the shaft.
IMA of or less than 1When a machine's input and output distances are the same, it means that the ideal mechanical advantage is one. Therefore, the amount of force that you exert on it is equal to the amount of force it exerts on the load. But don't forget, this isn't actually true, ideal mechanical advantage does not take friction into account, therefore the input force is actually slightly higher than the output force. When a machine's input distance is less than its output distance, it means that the ideal mechanical advantage is less than one. This means that you will exert more force into the machine than it will exert on the load. This may sound pointless to use, but what we lose in force, we gain in speed and distance, the speed at the output is actually greater and it travels further than the input. this is useful for things such as baseball bats, hockey sticks, and golf clubs, where you need a high speed. Friction and Perfect MachinesThe ideal mechanical advantage of a machine is always higher than its mechanical advantage. This is because mechanical advantage takes into account the friction that requires you to exert more force on the machine to move the load, thus making the input force even greater. So what is friction anyway? Well, friction is a force that resists motion between two surfaces in contact. It wastes some of the energy you put into the machine by transforming it into heat energy. It occurs on all the moving parts of a machine, such as the point of a lever's fulcrum, or the load moving along an inclined plane. The more surface area that rubs against other surfaces there is, the more friction there is in a machine, causing it to require a higher input force to move the load. Therefore, a machine that doesn't have any friction, also called a perfect machine, would have its IMA equal to its MA, and a machine that has a lot of friction, would have an IMA that is a lot greater than its MA. The only problem... there is no such thing as a perfect machine, but we can use lubricants, such as oil, to lower the amount of friction in a machine.
Machines such as inclined planes that have a lot of surface are rubbing against each other have more friction, making their IMA much higher than their MA. On the other hand, machines such as levers which have a very little amount of rubbing surface area, only the tip of their fulcrum, have very little friction, thus causing their IMA and MA to be almost identical.
What is Ideal Mechanical Advantage?The ideal mechanical advantage of a machine is its mechanical advantage, not including the work done by the force input force that ends up getting wasted as heat because of friction. In other words, it is what the mechanical advantage of a machine with zero friction would be. The ideal mechanical advantage is determined by the ratio of the distance over which the input force is exerted on the machine, to the distance over which the output force is exerted on the load.
Therefore, the greater the distance over which the input force is exerted on the machine (the input distance), compared to the distance over which the output force is exerted onto the load (the output distance), the greater the ideal mechanical advantage is. The greater the ideal mechanical advantage is, the less force will be required to move the load, although the input force will have to be distributed over a greater distance. Since the ideal mechanical advantage is just a ratio comparing the two distances, there is no specific unit to measure it, just a number.
What's the difference between MA and IMA?The main difference between ideal mechanical advantage and mechanical advantage is that the mechanical advantage takes into account the friction that wastes energy as heat in all machines, but the ideal mechanical advantage doesn't. This is because mechanical advantage compares the input and output forces, which vary depending on the amount of friction in the machine, but ideal mechanical advantage compares the distances over which those forces are applied, so it doesn't take into account the amount of friction.
Levers, Inclined Planes, Pulleys, and Wheels and AxlesThe input distance is the distance over which you exert a force on a machine to move a load, and the output distance is the distance you would have to move the load without the machine, how much the load moves.
On a lever, you can calculate the IMA two ways, you can use the ratio of the input distance, the output distance. Or, you could use the ratio of the length of the effort arm, to the length of the load arm. Just be careful that you do not use a ratio comparing the input or output distance and the length of an arm, this would not give you the IMA. This is because the distances traveled can be different to the length of the arms, but they have the same ratio.
On an inclined plane, the input distance is the length of the top of the inclined plane because that is the distance the load is pushed, and the output distance is the height of the inclined plane, because that is the height the load reaches.
On a fixed pulley, the ideal mechanical advantage is always one, but the direction of the input and output forces are opposites. On a movable pulley or a pulley system, you find the ideal mechanical advantage by counting the number of support ropes.
On a wheel and axle, instead of comparing the input and output distances to find the IMA, you would compare the radius of the axle and the radius of the wheel. If you were applying the input force to the wheel, the IMA would be the ratio of the wheel's radius to the axle's, and it would always be greater than 1. If you were applying the input force to the axle, the IMA would be the ratio of the axle's radius to the wheel's, and it would always be less than 1. For example, when you hold a screwdriver's handle, you would need to exert less force than you would if you held onto the shaft.
IMA of or less than 1When a machine's input and output distances are the same, it means that the ideal mechanical advantage is one. Therefore, the amount of force that you exert on it is equal to the amount of force it exerts on the load. But don't forget, this isn't actually true, ideal mechanical advantage does not take friction into account, therefore the input force is actually slightly higher than the output force.
When a machine's input distance is less than its output distance, it means that the ideal mechanical advantage is less than one. This means that you will exert more force into the machine than it will exert on the load. This may sound pointless to use, but what we lose in force, we gain in speed and distance, the speed at the output is actually greater and it travels further than the input. this is useful for things such as baseball bats, hockey sticks, and golf clubs, where you need a high speed.
Friction and Perfect MachinesThe ideal mechanical advantage of a machine is always higher than its mechanical advantage. This is because mechanical advantage takes into account the friction that requires you to exert more force on the machine to move the load, thus making the input force even greater. So what is friction anyway? Well, friction is a force that resists motion between two surfaces in contact. It wastes some of the energy you put into the machine by transforming it into heat energy. It occurs on all the moving parts of a machine, such as the point of a lever's fulcrum, or the load moving along an inclined plane. The more surface area that rubs against other surfaces there is, the more friction there is in a machine, causing it to require a higher input force to move the load. Therefore, a machine that doesn't have any friction, also called a perfect machine, would have its IMA equal to its MA, and a machine that has a lot of friction, would have an IMA that is a lot greater than its MA. The only problem... there is no such thing as a perfect machine, but we can use lubricants, such as oil, to lower the amount of friction in a machine.
Machines such as inclined planes that have a lot of surface are rubbing against each other have more friction, making their IMA much higher than their MA. On the other hand, machines such as levers which have a very little amount of rubbing surface area, only the tip of their fulcrum, have very little friction, thus causing their IMA and MA to be almost identical.