Pulley Task

[fleet130]

So the ratio of this pulley system is 3:1 right? In order to raise the mass 15cm, the string would have to be pulled at least 45cm?

That's correct! Ideal Mechanical Advantage (IMA) is the ratio of the output & input forces. It is equivalent to the ratio of the input and output distances.

Note: In the diagram above, the outputs of the second (smaller) fixed pulley and the movable pulley are both connected to the blue load, summing their forces, creating an IMA of 3.

[illusionist]

If I was to use string running through holes in the blocks, and then pulling the string vertical to raise the blocks method, could I use the pulley system to raise the blocks. But then the pulley system isn't actually going to "lift a mass". Could I tie a mass to the end of the string in the pulley system, and then attach the string for the blocks onto the mass?
Did that make any sense?