Homework Help

Hello! I am working on a problem to resolve the balance of forces on a seed (very small and disc shape) that is being 'captured' on the stream bank. The density of the seed is less than water thus it is buoyant (making the problem different than sediment deposition theory). I am assuming that the water is receding and the capture of the seed is the result of friction forces overcoming the pull force of the water. Would it be better to resolve this by thiking in terms of Net force= driving force/resisting force or solving the shear forces? Also, would surface tension or drag forces have to be considered? Any thoughts would be greatly appreciate or litera…

This isn't a homework question, I am just curious. With both fertilization and chemical synaptic transmission, I have learned that Ca+ causes a fusion of corticle granule and synpatic vesicles, respectively, to the plasma membrane. My textbook never states why, nor has my professor. I am confused as to how Ca+ induces such an instance. Could anyone give me some things to think about? Thanks.

hi struggling with this problem, don't understand the topic recursion Exercise 3. Let f(n) = f(ceiling n/2)+n, and let g(n) = g(n􀀀1)+2n with g(1) = 0. Calculate the following values by unfolding. 1. f(5) 2. f(9) 3. g(6) 4. g(9) any advice or help would be appreciated regards im not looking for answers just a bit of advice or an example. i have james hein s book on discrete maths , logic and computability

Hello. I'm not sure if there is one or not, but what is the difference between pollen and spores? I honestly can't think of a single one.

Hey. I'm new here. I am in 8th grade science, and my teacher assigned a topic for each student to research and make a project on. None of us in the class know anything about the topics. I received Superconductors. I have to answer 4 questions: 1) What was the scientific question they were asking? 2)What did the scientists think before? 3) How did they make their discovery? 4) How did their discovery change what other scientists did or thought? For 1, I am pretty sure that the question was: What happens to mercury when it is cooled to super low temperatures. For 2, I cannot find anything about what scientists thought before. For 3, I can find this info on my …

Hi, I'm a high school student who has to run a self-designed lab. I'm supposed to see the affects of a carcinogen on a living organism. In this lab, there has to be 5 increments/ manipulated variables (cannot be time) and three responding variables. It's also preferable that it doesn't take too long to do, maybe MAX 1 + 1/2 weeks. However, I'm having trouble thinking of ideas. 1) The carcinogen : What can I use that is (relatively) safe and accessible? I do not have access to many chemicals (unless i make it myself), and even then I'm afraid that too much exposure can lead to some health problems. I considered radiation, but I'll need strong ones, …

Hi all, im doing first year biochemistry in an undergraduate degree. I have an exam coming up this week and am doing all my essay practice questions, i just cannot figure out what this question is asking me to do ? I can explain what each of a, b and c are, but i don't understand and cannot find out how they determine the activity of biomolecules? QUESTION Give an example to illustrate the significance of a. enantiomers b. conformers and c. geometric isomers in determining the activity of biomolecules. Does anyone have any suggestions on what i can research or can point me in the right direction for me to answer this question? thanks

I've got a chemistry practical exam, and in preparation for it, we have to devise tests for certain anions/cations. I need a bit of help for the Nitrate Ion (NO3-. is there any test that you can perform on nitrate to get a distinctive reaction? precipitation reactions are out, any Cations that might cause a precipitate to form would be unavilable in a school laboratory. is there any easy test? otherwise, I might just have to hope it isn't on the exam. I'm hoping to use the acetate ion when possible too so it won't interfere with any other things i'm testing for(because it's soluble with everything listed in my textbook, and so makes a good carrier ion) Other thing,…

"Treatment of 3-methylcyclohexene with HCl yields 2 products, 1-chloro-3-methylcyclohexane and 1-chloro-1-methylcyclohexane. Draw a mechanism to explain the result." I can't really figure out one can arrive at 1-chloro-1-methylcyclohexane, how did the positive charge manage to shift to the CH3 position? Also, I read another textbook, and it features a question which states that "reaction of HBr with 3-methylcyclohexene yields a mixture of four products: cis- and trans-1-bromo-3-methylcyclohexane and cis- and trans-1-bromo-2-methylcyclohexane". Then shouldn't the HCl reaction yield products of similar structure? Thank you.

I would like to know how to find the value for the spring constant from the graph of period against the square root of mass. I as study simple harmonic motion and I am using this equation: Period =2pi * square root * (mass/spring constant) I think that the gradient may help but not entirely sure. It it possible that i may need to find the gradient and use a formula to find out what the spring constant is. Thankyou

I have a sentence here which is rather vague. I do hope someone can shed some light on what's dead-end evolution. I did try browsing through the sites but no luck. Sentence: Porifera shows 'dead-end' evolution. This means that it represents the end of an evolutionary line. And what does it mean by representing the end of an evolutionary line? Any help is deeply appreciated.

Q: The escape speed from a very small asteroid is only 28 m/s. If you throw a rock away from the asteroid at a speed of 38 m/s, what will be its final speed? I know it's not 10 m/s. I was thinking of saying 28 = sqrt(2GM/Rinitial) to find the mass of the asteroid and then using that to find the final speed when it's thrown at 38 m/s, but then I also realized that I don't have the mass of the rock or radius of the rock, so that's out the window. Really, I'm not sure how to proceed, but this is what I know: Kball final + Kasteroid final + Ufinal = Kball initial + Kasteroid initial + Uinitial + W

Here's the problem: I completely understand how sexual reproduction occurs with mosses, they have sperm and eggs, but I have no clue where the asexual reproduction comes in. Do the gametophytes clone themselves or something? Please help!

Hello. I was studying for my bio exam when I came accross this question. I understand that these jellyfish are made up of Hydrozoans, but I'm not sure what exactly makes it a colony as opposed to anything else. Are Hydrozoans capable of surviving independently? Is it because Hydrozoans are themselves multicellular organisms? What exactly is the definition of a colony anyway? I could use some insight on this topic. Thanks.

1) Find each exact value of sin(x+y) if sin x=[math] \frac{3}{5}[/math] and sin y= [math] \frac{12}{37}[/math] I used the sin(x+y)=(sin x)(cos y)+(cos x)(sin y) formula, [math] \frac{3}{5} * \frac{35}{37} + \frac{4}{5}*\frac{12}{37}[/math] and got [math] \frac{153}{185}[/math] as a final answer. I'm second guessing my work because the answer doesn't seem like something my teacher would give. 2) How would I go about finding the ArcTan of 3? I know it's 71deg-ish, but I don't know how they got that... (Sorry about all the edits for this part of the post.) There might be more, I'm done with fifteen out of twenty problems. Thank you all for your help!

Hi, my name's scott and i'm currently in grad 11 chemistry, i hope this is the right place to post this :[ k so, we were given each a topic to research on and i'm doing PABA, i really need alot more information than i already have and i can't seem to find it, are there any sites someone can recommend for more data and stuff? the basic criteria for the project is: chemical structure and properties, risks and benefits to human health, and alternatives to using it. *to get a good mark or go beyond, including figures/tables is good* however idk wut tables or figures i could get and why is it dangerous?

Hi, I need to analyse some data I've collected and am trying to determine which stat method to use. I think a two-way ANOVA is the one I am after; but am not entirely sure what the variables are. I applied 16 perturbations to the backs of 8 men and 8 women ('pushes' of varying force, determined with a force gauge), before and after fatiguing their spines. I measured the muscle electrical response (EMG) as both the peak magnitude, and the reflex delay (time it took for the muscles to respond to the perturbations). I want to know what effect fatigue had on everybody before and after fatigue (magnitude and reflex delay), and the effect of fatigue between men and …

Hi, A total of 4543 patients were tested. A total of 300 patients had cancer. A total of 250 patients tested positive for cancer, of which 84% had cancer. I need to work out the true positives, false postives, true negatives and false negatives. How would I go about finding this out from this type of data. please help

The Problems: The following pictures are my work for the problems(in order) Thank you for your time.

hey all! this is my first time on a science forum... mainly because i just cant get this problem! Hopefully someone here can help me out... Jacob and Monod used the F’ plasmid in their experiments with the lac operon and constructed merodiploids (partial diploids in which there are two copies of some genes (See figure 17.10) For each of the merodiploid strains containing the lac Operon alleles listed, indicate whether the strain is inducible, constitutive, or unable to express β-galactosidase and permease. Strain β-galactosidase Permease a. I+ O+ Z-Y+ / I+ Oc Z…

Problem stumped me: If a laser emits 1.3 times 10^-2 J of energy during a pulse, how many photons are emitted during the pulse? E=hv where h is plancks constant 6.626 times 10^-34 j-s v would be the frequency. From what I understand, the problem is giving me E, but I'm stuck on the rest. Just need a clue on where to go from here.

well i have a science fair project that has to do with planaria dissection (its the effect of feeding on the regeneration of planaria). and i've searched everywhere but i cant find how much to feed my planaria. i have a low budget so i dont want to go out and buy much unless its at a low cost. they say planaria eat hard boiled egg yolk but how many grams should i give about 7 planaria? i just need this information to help me move on with my project. help please?

Hi, I need help on this graph question. Plot the %CV against the determinations of your pipetting and that of your partner, when using an automatic pipette compared with a glass pipette for flask 1. I have calculated the %CV values for my data and partners data for both pipettes. But I dont understand what kind of graph will be used here, and what would I plot against them ? do they mean absorbance values against the CV values ? please help. very worried

I need to describe what a standard operating procedure is and what procedures it may involve. Thankyou.

I have a media studies assignment set for homework due Monday that has to be within a 500 word limit. I am at exactly 900 words but may have to write more...Can you help me. This is actually not necessarily for media studies assignments...Many other subjects [including science] have written assignments with word counts. [below post ways you can lower how much you have typed/ how to stick to a specific word count.]