Suppose that the pulley in the below image is connected to something weighing 10 kg, and I need to pull on it with 9 N of force to hold it up. What's the efficiency? [img]http://02.edu-cdn.com/files/89501_89600/89569/file_89569.jpg[/img]
Simple Machines B/Compound Machines C Question Marathon
- Mathdino
- Member
- Posts: 24
- Joined: September 21st, 2012, 1:46 pm
- Division: C
- State: NV
- Has thanked: 0
- Been thanked: 0
Re: Simple Machines B/Compound Machines C Question Marathon
"If, in other sciences, we are to arrive at certainty without doubt, and truth without error, it behooves us to place the foundations of knowledge in mathematics."
-Roger Bacon, The Opus Major of Roger Bacon
-Roger Bacon, The Opus Major of Roger Bacon
-
- Member
- Posts: 19
- Joined: March 1st, 2012, 4:36 pm
- Division: C
- State: TX
- Has thanked: 0
- Been thanked: 0
Re: Simple Machines B/Compound Machines C Question Marathon
I'm not so sure about this but I'll give it a shot...Mathdino wrote:Suppose that the pulley in the below image is connected to something weighing 10 kg, and I need to pull on it with 9 N of force to hold it up. What's the efficiency? [img]http://02.edu-cdn.com/files/89501_89600/89569/file_89569.jpg[/img]
IMA = (Force out of the machine)/(Force into the machine). So for this scenario, the Force into the machine would be 9N, I think. And the Force out of the machine would be 10kg * 9.8m/s/s = 98N. Therefore, the IMA = 98N/9N = 10.89? I feel like I need to use the visual somehow, but this is what I ended up doing... :?
- chinesesushi
- Member
- Posts: 259
- Joined: September 17th, 2013, 4:57 pm
- Division: C
- State: CA
- Has thanked: 0
- Been thanked: 13 times
Re: Simple Machines B/Compound Machines C Question Marathon
But I believe Mathdino is asking for the efficiency in the problem, not the IMA?lchs wrote:I'm not so sure about this but I'll give it a shot...Mathdino wrote:Suppose that the pulley in the below image is connected to something weighing 10 kg, and I need to pull on it with 9 N of force to hold it up. What's the efficiency? [img]http://02.edu-cdn.com/files/89501_89600/89569/file_89569.jpg[/img]
IMA = (Force out of the machine)/(Force into the machine). So for this scenario, the Force into the machine would be 9N, I think. And the Force out of the machine would be 10kg * 9.8m/s/s = 98N. Therefore, the IMA = 98N/9N = 10.89? I feel like I need to use the visual somehow, but this is what I ended up doing... :?
1.36
Never argue with an idiot, they will drag you down to their level and then beat you with experience.
Before you criticize a man, walk a mile in his shoes. That way you'll be a mile away and he'll be shoeless.
You should only create problems, that only you know solutions to.
Before you criticize a man, walk a mile in his shoes. That way you'll be a mile away and he'll be shoeless.
You should only create problems, that only you know solutions to.
- Mathdino
- Member
- Posts: 24
- Joined: September 21st, 2012, 1:46 pm
- Division: C
- State: NV
- Has thanked: 0
- Been thanked: 0
Re: Simple Machines B/Compound Machines C Question Marathon
chinesesushi wrote:But I believe Mathdino is asking for the efficiency in the problem, not the IMA?lchs wrote: I'm not so sure about this but I'll give it a shot...
IMA = (Force out of the machine)/(Force into the machine). So for this scenario, the Force into the machine would be 9N, I think. And the Force out of the machine would be 10kg * 9.8m/s/s = 98N. Therefore, the IMA = 98N/9N = 10.89? I feel like I need to use the visual somehow, but this is what I ended up doing... :?
1.36
The [u]AMA[/u] is the (force out)/(force in), not IMA; lchs got the AMA correctly. Efficiency is AMA/IMA. chinesesushi almost got it, but I assume you got the IMA as 8 instead of 16. Notice that there are 4 class 2 pulleys and 2 class 1 pulleys, and 1*1*2*2*2*2=16. Efficiency is 10.89/16, or about 68.06%. Edit: A simpler way to explain it is that the IMA of the pulley on the right is 4 (count the rope sections) and the IMA of the one on the right is 4 (count). 4*4=16.
Edit: I derped and got a slightly wrong answer the first time. Fixed.
Last edited by Mathdino on December 26th, 2013, 11:38 pm, edited 1 time in total.
"If, in other sciences, we are to arrive at certainty without doubt, and truth without error, it behooves us to place the foundations of knowledge in mathematics."
-Roger Bacon, The Opus Major of Roger Bacon
-Roger Bacon, The Opus Major of Roger Bacon
- chinesesushi
- Member
- Posts: 259
- Joined: September 17th, 2013, 4:57 pm
- Division: C
- State: CA
- Has thanked: 0
- Been thanked: 13 times
Re: Simple Machines B/Compound Machines C Question Marathon
Yeah, I was trying to figure out why the efficiency was greater than 1.Mathdino wrote:chinesesushi wrote: But I believe Mathdino is asking for the efficiency in the problem, not the IMA?
1.36Your turn, chinesesushi.The [u]AMA[/u] is the (force out)/(force in), not IMA; lchs got the AMA correctly. Efficiency is AMA/IMA. chinesesushi almost got it, but I assume you got the IMA as 8 instead of 16. Notice that there are 4 class 2 pulleys and 2 class 1 pulleys, and 1*1*2*2*2*2=16. Efficiency is 10.36/16, or about 64.75%. Edit: A simpler way to explain it is that the IMA of the pulley on the right is 4 (count the rope sections) and the IMA of the one on the right is 4 (count). 4*4=16.
[img]http://www.gweaver.net/techhigh/projects/Rube%20Goldberg/Rube%20Goldberg%20Websites/Period%205/Rube%20Website%20Kyle,%20Jared,%20Sam,%20Nicole,%20Arlene/Images/animatedfourpulley.gif[/img] What is the IMA of the pulley system and how much force is required to lift it the appropriate amount. The pulley is in an ideal state.
Never argue with an idiot, they will drag you down to their level and then beat you with experience.
Before you criticize a man, walk a mile in his shoes. That way you'll be a mile away and he'll be shoeless.
You should only create problems, that only you know solutions to.
Before you criticize a man, walk a mile in his shoes. That way you'll be a mile away and he'll be shoeless.
You should only create problems, that only you know solutions to.
-
- Member
- Posts: 91
- Joined: March 26th, 2013, 4:58 pm
- Division: C
- State: PA
- Has thanked: 0
- Been thanked: 0
Re: Simple Machines B/Compound Machines C Question Marathon
Im new at this event, but here is what I think
IMA of a pulley is number of supporting strings or input d / out put d which is 4.
Ama=Ima in a perfect world so . . . 200/x=4
x=50 Newtons?
I think
IMA of a pulley is number of supporting strings or input d / out put d which is 4.
Ama=Ima in a perfect world so . . . 200/x=4
x=50 Newtons?
I think
- chinesesushi
- Member
- Posts: 259
- Joined: September 17th, 2013, 4:57 pm
- Division: C
- State: CA
- Has thanked: 0
- Been thanked: 13 times
Re: Simple Machines B/Compound Machines C Question Marathon
Sciolapedia wrote:Im new at this event, but here is what I think IMA of a pulley is number of supporting strings or input d / out put d which is 4. Ama=Ima in a perfect world so . . . 200/x=4 x=50 Newtons? I think :?
Close. The IMA is 4. You can do it either the way your did it or by D(in)/D(out) which is 4 m/1 m = an IMA of 4. However, the reason the answer is not 50 Newtons is because the [b]mass[/b] of the object is 200 kg, not the weight. The weight (or force) would be 200 kg * 9.8 m/s^2 = 1960 N. Therefore, the force needed to support the object would be 490 Newtons.
Never argue with an idiot, they will drag you down to their level and then beat you with experience.
Before you criticize a man, walk a mile in his shoes. That way you'll be a mile away and he'll be shoeless.
You should only create problems, that only you know solutions to.
Before you criticize a man, walk a mile in his shoes. That way you'll be a mile away and he'll be shoeless.
You should only create problems, that only you know solutions to.
-
- Member
- Posts: 91
- Joined: March 26th, 2013, 4:58 pm
- Division: C
- State: PA
- Has thanked: 0
- Been thanked: 0
Re: Simple Machines B/Compound Machines C Question Marathon
Yeah sorry I was writing my response and didn't want to hit the back button and see what unit it was. I just assumed it was newtons. But thanks anyways.
Explain the force distance trade off of work. Use at least one example from the inclined plane family and the pulley family to back up your answer(show how changing input distance and force changes output distance and force in that example).
Explain the force distance trade off of work. Use at least one example from the inclined plane family and the pulley family to back up your answer(show how changing input distance and force changes output distance and force in that example).
-
- Member
- Posts: 69
- Joined: February 18th, 2012, 7:19 pm
- Division: C
- State: NY
- Has thanked: 0
- Been thanked: 0
Re: Simple Machines B/Compound Machines C Question Marathon
Sciolapedia wrote:Explain the force distance trade off of work. Use at least one example from the inclined plane family and the pulley family to back up your answer(show how changing input distance and force changes output distance and force in that example).
in order to do the same amount of work with less force, the distance over which the force is applied must be greater. e.g. With an inclined plane, in order to raise the object a certain height with less force, the slope of the inclined plane must be lower, resulting in a greater distance required to push the object to attain the same height. In the pulley family, in order the raise an object the same height with less force, the amount of strings supporting the object must increase thereby increasing the distance required to pull the leading rope to raise the object.
Looking forward to anatomy, protein, fossils, and optics (NYS trial) this year!
-
- Member
- Posts: 91
- Joined: March 26th, 2013, 4:58 pm
- Division: C
- State: PA
- Has thanked: 0
- Been thanked: 0
Re: Simple Machines B/Compound Machines C Question Marathon
Great Job
(though maybe I would have talked about the formula a bit also)
YOUR TURN
(though maybe I would have talked about the formula a bit also)
YOUR TURN
Who is online
Users browsing this forum: No registered users and 7 guests