Simple Machine
A pulley is free to spin
A pulley can change the direction of the force or increase the output force, depending on whether the pulley is fixed or movable
Fixed pulleys can only change the direction of the force
If one end of a pulley is fixed and the pulley is allowed to move, you have a movable pulley
The ideal mechanical advantage of a pulley system is equal to the number of support ropes
A combination of a fixed and movable pulley can produce various mechanical adavntages
A pulley consists of a grooved wheel with a rope of cable around it
Since the output force is the same as the input force, a fixed pulley has a mechanical advantage of 1
When an input force is applied downward on the rope, the output force is in the upward direction
The wheel and axle consists of a shaft and an axle which is attached to a larger disk
When ever you use a screwdriver, the handle of the screwdriver is the wheel, and the the shaft is the axle
Both the wheel and axle rotate around the center of the wheel, if an input force acts on the wheel, then the output force provided by the axle has an ideal mechanical advantage of greater than 1
When you use a screwdriver, you are using it to increase the output force
If the input force is applied to the axle, the ideal mechanical advantage can be calculated by:
Ideal Mechanical Advantage= radius of axle / radius of wheel
If the input force is applied to the wheel, the ideal mechanical advantage can be calculated by:
Ideal Mechanical Advantage= radius of wheel / radius of axle
A sloping surface on which an object can move on is called an inclined plane
An inclined plane reduces the force needed to move an object
Ideal Mechanical Advantage= length of ramp / height of ramp
Inclined planes are used everyday, like a wheelchair ramp or even your stairs are inclined planes
Inclined planes make you move without using a lot of force
The formula for IMA of an inclined plane is just l/h
A screw is simply an inclined plane wrapped around a rod
The continuous inclined plane starting from the top is called a "thread" The length of the thread is longer than the height of the screw
A wedge is also an inclined plane that travels through an object or material
One way a wedge is used is to split firewood
The longer and narrower the wedge, the more ideal mechanical advantage
A mechanism is a when there are two or more simple machines working together