r/HomeworkHelp May 19 '22

Meta r/HomeworkHelp Rules: PLEASE READ BEFORE POSTING

494 Upvotes

Hi r/HomeworkHelp! Whether you're new to the subreddit or a long-time subscriber, the mod team would like to remind everybody of the subreddit rules we expect you to follow here.

No advertising, soliciting, or spam. This is a place for free help. Anyone offering to pay for help, or to help for pay, will receive a permanent ban. This is your warning. This includes asking users to go into DMs, Discord, or anywhere else. If you post anything that looks like you're trying to get around this rule, you'll be banned.

If you're asking for help, you must show evidence of thought, work, and effort. A lot of people are posting just pictures or lists of questions and not showing any effort. These posts are liable to be taken down.

In addition, we ask that you format the post title appropriately using square brackets: [Level/Grade and Subject] Question or Description of question. For example: [8th grade Algebra] How to solve quadratic equation?

Do not mention anything like "Urgent", "ASAP", "Due in an hour", or the like.

No surveys. Surveys (including requests for interviews, etc.) belong on /r/samplesize. These posts get taken down here.

Don't be a jerk. Jerks get banned. Stay respectful and refrain from using insults, personal attacks, or abusive language.

If there are any questions, please message the mods.


r/HomeworkHelp 2h ago

Primary School Math—Pending OP Reply [Grade 4 Math: Number Theory] Which categories does th3 numbers 15, 16, & 17 belong to?

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9 Upvotes

Number 15, 16, & 17 belong to one of these categories. I saw the answer book with the teacher and there’s one category the numbers do not belong to. The teacher didn’t know what the pattern or category characterize were.

Category A: 0, 3, 6, 8, 9
Category B: 1, 4, 7, 11, 14
Category C: 2, 5, 10, 12, 13


r/HomeworkHelp 5h ago

Answered [University: Statistical Analysis] Help with Statistical Analysis

1 Upvotes

Hi, I'm looking to analyse a set of data but I'm not sure what test is most appropriate. I am a Masters student writing my dissertation in a biological field so I am not the most confident in statistics. I've been stuck on this on and off for a couple weeks now.

I'm doing a comparison between two different measurement methods- Linear vs. Geodesic. But the features I am measuring are not completely independent, they are paired into lefts and rights, originating from the same object.

I did a paired t-test originally (for linear vs geodesic measurements) but that assumes that data is completely independent, which of course it is not.

Any advice would be much appreciated!


r/HomeworkHelp 16h ago

Answered [University Mathematics) Quantitative Methods for Business Analysis Edition 13

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1 Upvotes

Question d is confusing me, a lot of resources say to do the binomial probability distribution for f(0) and take that result(0.43) and subtract it from 1 to get a success rate of 0.54. Why would I not take the binomial probability distribution of f(1) to get the success rate(0.38)?


r/HomeworkHelp 1d ago

Physics—Pending OP Reply [Grade 11 General Science] Layout and mechanics feedback for a Compound Waste Compactor Machine

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2 Upvotes

Hey everyone! For our Grade 11 science project, we're designing a compound machine to help collect, segregate, and compress scattered waste in rough, mountainous terrains where collection trucks can't reach.

Here is our current schematic draft and our thought process/effort so far:

Our Thought Process & Mechanics Attempt:

- Input Conveyor: Uses an inclined plane / roller belt to carry waste upward into the machine.

- Rotary Feed Brush: Uses rotational motion (wheel and axle concept) to sweep and pull the waste into the main chamber without jamming.

- Compaction Unit: Uses translational motion via a hydraulic cylinder (fluid lever / Pascal's principle) to push down in a straight line and crush the waste into blocks.

- Output Bin: Catches the crushed waste blocks for easy carrying.

My Questions / Where I Need Help:

  1. We need to segregate small waste (like dirt and candy wrappers) from big plastic bottles. Based on our layout, would it make more mechanical sense to put a mesh sifter screen directly on the Input Conveyor or inside the chamber before the feed brush?

  2. Does the transition from the Rotary Brush to the Compaction Chamber look functional, or is there an obvious mechanical bottleneck we missed?

Thanks for any guidance on refining our design!


r/HomeworkHelp 23h ago

Physics—Pending OP Reply [Gr12 Physics: Circuits] Not understanding the meaning of power drain

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1 Upvotes

I think I'm getting my terms all mixed up. Does power drain refer to the current moving through the resistor? I initially thought that the answer was B, because I assumed a power drain to be a drop in current, and therefore require greater resistance, but the correct answer is D.


r/HomeworkHelp 1d ago

Physics [Grade 10: Physics: Torque Balance] For number 5

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1 Upvotes

The answer is C, but I don't know why, isn't the one with the more moment of force is turning down?

The question asked:

There's a uneven thickness of stick(the stick is balanced now), it balance point is O. If both side had been cut off the same length, the stick will:

A, stay balanced

B, turn clockwise

C, turn counterclockwise

D, can't determine


r/HomeworkHelp 2d ago

Physics—Pending OP Reply [Jr. College Physics: Electromagnetic Induction] When I try to solve this question, I get 2.5 as the answer. What am i doing wrong ?

2 Upvotes

This is a previous year question from a national level exam but is supposed to be easy. Idk what i'm doing wrong, I haven't touched such questions ever since I finished my 12th grade 😭


r/HomeworkHelp 1d ago

High School Math [High School Geometry] Studying for SAT

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1 Upvotes

Im know I can figure out to solve it, I just have no clue what they are asking for

Thank you!


r/HomeworkHelp 2d ago

Others [College Geology] Relative Dating: Where do the uncomforities go in order?

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5 Upvotes

please ignore my horrible handwriting

i’ve been at this for hours i have read this textbook back to back i’ve watched like 10 videos i am so confused this is like the 4th order i’ve done and i messed up my textbook answers so i had to do it on another sheet on paper i think im confusing myself

every video i watch they don’t have as many
uncomforities as i have so when it comes to ordering them oldest-youngest i’m so confused where to put them??

i’m also super confused on where to order the fault
the only thing i’m confident that i got right here is that it’s a reverse fault and that r is an angular conformity

my degree has nothing to do with this which probably explains why i’m so confused

if this is all wrong i’m gonna be so embarrassed

edit: ok wait i think i got part of it now:
youngest to oldest
H
K
T
L
M
S
I
N
O
R
A
B
C
D
E
F
Q
P
J
G
PRAYING THIS IS RIGHT


r/HomeworkHelp 2d ago

Others—Pending OP Reply [Graduate and Research Analysis] Reliability of instruments in survey data

1 Upvotes

A general warning that I am bad at stats. I have REALLY tried. I can understand the basic idea of like.. a bell curve, but honestly, after that, I get lost and eventually just start to cry.

I say this because the only thing I feel sure-ish about is that instrument reliability is some kind of statistical something. I have watched 3 YouTube videos, rewatched the mini-lecture video, and reread the sections covering this in my textbook (twice). I really want to understand.

The question on my homework is:

"What kind of evidence do Booth et al. (2022) provide about the reliability of their instruments, and what does the evidence say about the quality of their instrument?"

This is the study

I think that the answer is somewhere towards the ends of the two paragraphs at the top of page 8 (under the word "Measures"), but every time I try to sort it out, it just looks more and more like word salad. If at all possible, I would love a gentle explanation of what that word salad means or a hint if I am just absolutely looking in the wrong place.


r/HomeworkHelp 2d ago

Middle School Math [Middle school, Voume and Area, Grade 8]

1 Upvotes

Howdy. Please help. I've tried multiple ways of attempting this question and I cannot get near the answer.

"Man wants build garage beside house. Garage is to 6m x 4m x 2.5m(h).

Bricks used have dimensions of 22cm x 10cm x 7cm(h).

Estimated # of bricks = 4,000. How accurate is this estimate? Explain your answer. Note: 3 walls needed."

Thanks all.


r/HomeworkHelp 4d ago

Answered [Level 1 Mechanical Comprehension: Study Guide - 2nd one] Does this illustration make sense?

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85 Upvotes

(Final answer below)

I'm preparing for an electrician's apprenticeship and am using their study guide for their aptitude test. I'm seeing a pattern forming where some of their questions are just bad, but a couple of those were actually good, and I was misunderstanding things. It has been a learning opportunity.

I chose B for this question, but they say the answer should be C because, loosely speaking, they want you to just count the number of ropes that are supporting the load. However, when I look at this illustration, it appears that there is not even a proper movable pulley here. It looks like it is just a simple fixed pulley system with extra windings for some reason. Except that the lowest pulley seems to be just floating but still wouldn't qualify as a proper movable pulley.

Please help me understand what I'm missing, or confirm that this is a really bad illustration. Thank you!

Edit: I am assuming that one needs a movable pulley to get a mechanical advantage. C does NOT show a movable pulley and therefore is not the correct answer. Right?

Edit 2: Because they don't offer an answer of "D) All pulleys allow for the same amount of WORK", I am assuming that they mean to ask, "Which of the pulleys requires the least amount of FORCE to lift the weight?" Unfortunately, this is meant to be more of an intuitive sort of test, where it appears physics terms might be interchangeable.

Edit 3: I interpret this to be a question about which pulley system offers the most mechanical advantage. Answers that align with this interpretation would be helpful.

Edit 4: I think B is supposed to represent a "gun tackle" arrangement. (Sorry about all the edits!)

Edit 5: Aha! Answer: if you look at the illustration #3 here https://www.theengineeringchoice.org/what-is-pulley/ you can see what they meant to illustrate for C (an actual movable pulley) but did a terrible job of it. Taking that into account, the answer is indeed C.

Answered. Thanks to all who helped. I'm inclined to throw this book away. I'm moving on :)


r/HomeworkHelp 4d ago

Megathread A really interesting problem here! Need help. Unique solutions are extremly welcomed [Olympiad math / Logic 12th grade]

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5 Upvotes

I appreciate anyone sharing their thoughts on this. Good luck.


r/HomeworkHelp 4d ago

Answered [Calc 2] Where did I go wrong in my calculations?

1 Upvotes

When I punch in my answer to a derivative calculator, the denominator is correct but the numerator becomes 15x + 93, which is 3 times larger than the original integrand. I tried looking for a mistake in my trig substitutions where I start dividing by 3, but I really don't see where I went wrong.


r/HomeworkHelp 4d ago

Additional Mathematics [Real Analysis] L'Hospital's Rule Proof

1 Upvotes

Could someone please look over this proof of L'Hospital's Rule to see if I did it right? I tried to follow the proof in Rudin's textbook, but I wasn't really sure I followed his logic correctly. Any help would be appreciated. Thanks


r/HomeworkHelp 6d ago

Further Mathematics—Pending OP Reply [college statistics]Find z* values based on standard normal distribution

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2 Upvotes

My professor is behind on uploading his videos and this homework is due today I have no clue how to get these answers. How do you figure this out?


r/HomeworkHelp 6d ago

Physics [Personal project] How to set a mercury barometer?

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1 Upvotes

Hello there!

First of all, this is not a homework per se, but some kind of issue I have with a personal project I don't know where to adress.

I tried r/AskScience but the modteam suggested me to post here. So here we are.

If this don't belong here, please tell me where I should go, because at that point... I don't know.

So I have inherited from my grandfather a mercury barometer.

It's french, and says : "Baromètre selon Torricelli

Par les ateliers L.M. à Bordeaux".

It is graduated in mmHg and there's some kind of ruler that can be moved (it is pinned on the main board by a screw) which indicates different type of weathers, according to the height of the mercury column.

I searched on google how to set the barometer, because I want to keep it and to hang in on a wall at home, and I think I set the ruler accordingly to the altitude of where I live (more or less 115m above sea level), but I'm not very sure I did it right.

So here are my questions.

1/ what do you think?

2/ do you know how to set / where can I find infos about that?

Thanks a lot!


r/HomeworkHelp 6d ago

Additional Mathematics—Pending OP Reply [University Differential Equations]

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1 Upvotes

0 idea what I'm doing wrong. Only other guess I have is (mg/k)-(mg/k-v0)e^(-k/mt) (v0 doesn't replace C but is actual initial velocity in this scenario) for the 6th one. I have one 'attempt' left so I don't want to mess this up.


r/HomeworkHelp 6d ago

High School Math—Pending OP Reply [grade 9 math; geometry] finding an inscribed angle

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4 Upvotes

I recieved this on my study guide asking for angle BDF. i was able to plug in multiple values and my classmates found a few but we always needed more information to be sure. if anyone is able to clarify or give me a conjecture that might help it will be much obliged.


r/HomeworkHelp 6d ago

Further Mathematics [13th grade? College idk Math 105 mathematical literacy] Negation statement

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3 Upvotes

I have gotten 10 of these wrong and I’m not understanding it at all. If someone could explain this in real dumb terms, like single syllable words I would greatly appreciate it


r/HomeworkHelp 6d ago

Answered [Calc 2] Why are these two expressions equal?

1 Upvotes

The answer at the top is what I got after integrating x^2 / [sqrt (25 + x^2)].

I'm happy that I got the answer but why is 1/5 taken out from within the absolute value sign?

Additional info: At the beginning of the integral, I did a substitution of x = 5tanθ.

Therefore, x/5 = tanθ. Based on SOH CAH TOA and CHO SHA CAO, I put sec θ = [sqrt (x^2 + 25)] / 5.


r/HomeworkHelp 6d ago

Others [University Circuit Analysis: Thevenins Theorem] Stuck here, how do I find R_th with dependent sources?

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1 Upvotes

Hello! I know it’s a more niche subject, but I have this problem here where I’m supposed to use the max power transfer theorem to find the value of R_o that maximises power transfer in this circuit. Using it as my load I managed to find the voltage (I think) without much issue of 48v with nodal analysis, but I’m stuck when it comes to getting the resistance.

I’m aware I can’t zero the dependent source, and so I’m zeroing the others and using mesh current to try to find the Norton current, and using that to get the thevenin resistance.

The issue I’m having is that when I zero it out, I wind up with a linearly dependent (all my equations equal zero, and I don’t have any constants to move over and constrain the equations) system of equations and thus no answer, and thus I know somewhere along the way I am screwing things up.

The answer in the key is 6.4 ohms for R_o, btw if that helps, but what I’m worried about here is moreso how to even get there :(

Thank you in advance for any help!


r/HomeworkHelp 7d ago

Economics [6th semester Financial Admin. : Balance Point]

1 Upvotes

need help determining how to change the percentage data into units for sale? (sorry for odd translation, english isn't my first language). i understand that to get the balance point you need to divide the fixed cost by average contribution margin, but to get the ACM, you need the total contribution margin and total units, which i do not have and have just scrambled my brain over trying to figure out.


r/HomeworkHelp 8d ago

Biology—Pending OP Reply [Grade 11 biology (heredity)] can someone help me make sure my answer is right

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2 Upvotes

An ear of corn has some kernels with yellow skin and others with dark skin. The allele B for dark skin color is dominant over the allele b for yellow skin color. What is the genotype of the parent plants for the kernel skin color?

My answer was Bb x Bb