Simple Machines B/Compound Machines C

Eggo
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Simple Machines B/Compound Machines C

Welcome to the Marathon for Simple Machines and Compound Machines!
Note: (I thought I might as well start a question marathon for Simple Machines and Compound Machines since no one else did. )
Lets start off with: What class of a lever is the human forearm and why?
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Re: Simple Machines B/Compound Machines C

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Eggo
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Re: Simple Machines B/Compound Machines C

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XturtleX
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Re: Simple Machines B/Compound Machines C

A pulley has an AMA of 4, it is used to lift up a 100 N block. How much force will someone have to exert to lift it.

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Re: Simple Machines B/Compound Machines C

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Re: Simple Machines B/Compound Machines C

Unome wrote:

Unome, your answer seems correct to me. Since the asker has not been on for a few days, feel free to go ahead and ask the next question.

$AMA = \frac{F_{out}}{F_{in}} \to 4 = \frac{100 \hspace{1} N}{F_{in}} \to F_{in} = 25 \hspace{1} N$
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Re: Simple Machines B/Compound Machines C

A 1st class lever exists with three weights. One side contains a 4.0 kilogram weight at 0.600 meters from the fulcrum, and a weight with a mass of K at 1.3 meters from the fulcrum. The other side has a 7.0 kilogram weight with a volume of 700. centimeters cubed immersed in water, at a distance of 1.0 meters from the fulcrum. Find K (Rounded to sigfigs)
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ageek
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Re: Simple Machines B/Compound Machines C

I'm not exactly sure what the "immersed in water" or the volume has on the effect, except that I can assume that it's balanced (I hope)
But here is my answer according to those assumptions

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Re: Simple Machines B/Compound Machines C

Unome wrote::twisted:
A 1st class lever exists with three weights. One side contains a 4.0 kilogram weight at 0.600 meters from the fulcrum, and a weight with a mass of K at 1.3 meters from the fulcrum. The other side has a 7.0 kilogram weight with a volume of 700. centimeters cubed immersed in water, at a distance of 1.0 meters from the fulcrum. Find K (Rounded to sigfigs)

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Re: Simple Machines B/Compound Machines C

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chinesesushi
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Re: Simple Machines B/Compound Machines C

who's correct?
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Re: Simple Machines B/Compound Machines C

What is the mechanical advantage of each of the pulleys. https://www.lhup.edu/~dsimanek/scenario ... ulley1.gif

If f = 10 N and L has a mass of 3 kg what is the AMA. What is the efficiency.
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Unome
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Re: Simple Machines B/Compound Machines C

chinesesushi wrote:

What is the mechanical advantage of each of the pulleys. https://www.lhup.edu/~dsimanek/scenario ... ulley1.gif

If f = 10 N and L has a mass of 3 kg what is the AMA. What is the efficiency.

Sorry, yes you were the correct one (Unfortunately, I can't also answer the question because the page won't load (it's a problem on my side not, with the image))
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Re: Simple Machines B/Compound Machines C

chinesesushi wrote:

What is the mechanical advantage of each of the pulleys. https://www.lhup.edu/~dsimanek/scenario ... ulley1.gif

If f = 10 N and L has a mass of 3 kg what is the AMA. What is the efficiency.

A) IMA=4, AMA=3, efficiency=75% (80% with sig figs)
B) IMA=32, AMA=3, efficiency=9.375% (10% with sig figs)
C) IMA=3, AMA=3, efficiency=100%
(these are assuming the gravitational constant is rounded to 10, because otherwise C's efficiency is above 100%)
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chinesesushi
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Re: Simple Machines B/Compound Machines C

a is right.
b is right.
c is wrong (btw why can't it be 9.8. AMA = 9.8*3/10 = 2.94. efficiency = AMA / IMA = 2.94 / 3 < 1)
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.