# Pulleys: How do they exactly work?

Having multiple pulleys reduce the amount of force you have to exert to pull up an object?

why is that exactly?

I mean, I use this principle whenever I encounter a pulley Q...w/o really understanding why that's the case...

Can someone expain in terms of Newtoniam mechanics and/or Free BOdy diagram?

$$F_1 = F_2\frac{D_2}{D_1}$$