# Increasing the number of pulleys

1. Jan 25, 2014

### Blonde1551

1. The problem statement, all variables and given/known data
I'm trying to do a lab and none of my data is making sense. It's making it very difficult for me to draw conclusions and make sense of the post-lab questions with the data I have.

Here are the questions I am struggling with:
1. What happens to the force exerted as mechanical advantage gets larger?
2. How does increasing the number of pulleys affect the ideal mechanical advantage and efficiency of a pulley system?
3. How does increasing the load affect the ideal mechanical advantage and efficiency of a pulley system?

2. Relevant equations

IMA = de/dr

MA = Fr/Fe

Efficiency = (MA/IMA) x 100

3. The attempt at a solution
This is what I am assuming but I don't really know.

1. I think the force gets smaller because the fr stays the same so to get a bigger MA you divide by a smaller number, plus the pulley makes it easier so you use less force. Would this be correct?

2.I assumed that increasing the number of pulleys will increase the IMA. But due to friction it will decrease the efficiency. The more pulleys that are turning, the more friction there is, and the less efficient the system will be. Would this be correct?

3. Increasing the load will add to the friction, thus reducing the efficiency of the system. The ideal mechanical advantage won't change since the IMA neglects friction. Does this make sense?