We're going to be using pulleys to pull two (or more) kids with one hand. You will be using something called ‘Mechanical Advantage’, which is like using your brains instead of brute strength. When you thread the rope around the broom handles, you use 'mechanical advantage' to leverage your strength and pull more than you normally could handle.
How can you possibly pull with more strength than you have? Easy - you trade ‘force’ for ‘distance’ - you can pull ten people with one hand, but you have to pull ten feet of rope for every one foot they travel.
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How can you possibly pull with more strength than you have? Easy - you trade ‘force’ for ‘distance’ - you can pull ten people with one hand, but you have to pull ten feet of rope for every one foot they travel.
Here's what you do: Please login or register to read the rest of this content.
that is so COOL
Great question! And kudos to you for wanting to do this for REAL! 🙂
How you calculate the force you pull and distance you travel really depends on how you string up the pulleys. Go back and watch the other video on pulleys were we show you how to do it with broomstick handles and counting the strings for the mechanical version of the pulleys. Note that you’ll also have friction, so whatever you calculate as your mechanical advantage, it is going to be a little off from what you actually experience. Try it with a 50 pound weight (bag of sand or dog food comes to mind) so that the kids don’t get hurt playing with heavy weights above their heads.
This was a cool experiment but I would like to use this in real world. We are building a tree house and we have a spiral staircase we believe weighs about 400 lbs. I have a concrete slab with a steel post sticking out to set the center of the staircase on. I will most likely hire someone to do this but…
I’d like the kids to calculate how to lift this staircase safely using the methods we have learned. What would be the best method to do that using pulleys?
WOW!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I never knew that pulleys where so cool!!!!
Hmmm…. you’re right- we’ll get this fixed and uploaded today… so check back later this afternoon. Sorry about that!
This video will not let me get past 1 minute and 50 seconds of it. When I get to that point in the video, it stops and restarts at the very beginning! I’ve tried to drag the bar past 01:50, but it won’t go-it just restarts at the beginning again. Has anyone else noticed this?
Sorry! Thanks, Aurora.
-Stephanie