block and tackle pulley systems?

Question

explain them to me.

especially finding # of strands, input force, and max wieght lifted.

Answer 1

A block and tackle pulley system makes it easier to lift a heavy object. The pulleys mean that you have to use less force to move an object, but you have to pull a lot more rope.

A good explanation (far better than I could write on short notice) is given at: http://www.howstuffworks.com/pulley.htm

Hope this helps.