Pulley systems are used in the real world to lift large masses onto tall heights. You might have seen the workers repairing the roof of a house and using the pulley system to lift their tools or materials to the roof. A pulley is an example of a simple machine.
The pulley system consists of one or more pulleys and a rope or a cable. The number of pulleys used may increase or decrease the mechanical advantage of the system. Generally, the higher the mechanical advantage is, the easier it is to lift the object that is being lifted.
Overall, no matter how easy it is to use the pulley system, the system itself is not very efficient due to the force of friction. For example, one has to pull two meters of rope of cable through the pulleys in order to lift an object one meter.
The applet below illustrates just that. Select the number of pulleys and drag the mouse to see the inefficiency of the system.
More force is exerted with one pulley.
It works much more effectively, and with greater dedication, focus, and commitment, than an ailing pulley does.
Mechanical Advantage!
a coumpound pulley is when there is a fixe pulley and movable pulley working together
That would most likely be a pulley. A pulley is essentially a wheel on an axle that usually has a groove in the middle of its circumference that holds a rope, cable, belt, or chain. Pulleys are used to transmit motion rotationally and apply force in the direction of said motion. Two or more pulleys makes a tackle. Hope this is what you were looking for.
A pulley man.
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A radio tuner uses wheels and strings (at least, they used to; modern radio tuners have more sophisiticated methods). A pulley generally uses wheels and ropes, but a very light-weight pulley might use strings instead of rope.
A pulley-man
pulley
a pulley a pump
The pulley.
flagpole
A clothes line uses a pulley, which is an ingenious simple machine. More complex uses of pulleys have certainly played a role in science and technology.
That is not always true. Sometimes a fixed pulley is more useful.
A tyre has more friction than a pulley.
When the receiver uses this response style he clarifies or seeks more information.