plz help on these 2 physics problems?

Question

1. The top pulley hanging from the support produces only a change in direction of the effort force and not any mechanical advantage. Explain.

2. Determine the relationship between the number of strands supporting a block and tackle and its mechanical advantage.

note that...
mechanical advantage=Resistance(load)N/Effort(force)
which is usually>1

* /Effort(force)

Answer 1

the first one.... imagine you have a 100 pound block on one side and ur on the other... you pull down but its still hard to lift it right? because you are pulling the whole 100 pounds... but it lifts it up because you are pulling down

when you think about pulleys always count the number of pulleys SUPPORTING the load and that is the machanical advantage

Answer 2

You have to think of it in terms of, "if i pull the rope one foot, how many feet do i lift the block" ? for question 1, the answer is 1.

for the second question, it's a 1:1 relationship!

http://science.howstuffworks.com/pulley.htm