Homework Help!

[Psychospacecow]

Thanks, a friend of mine stopped by around 6 and helped me through it.
I was really confused because it actually didn't give any numbers but I think I get it now.

[Ghost Nappa]

Create a conversation between the three Hominids who coexisted, Australopithecines, Homo Habilis and Homo Erectus. The conversation should include 2 direct or indirect references to the information recorded above about the specific hominid group. For example: "Good Morning Homo habilis, I see you are new to the scene here." This is making reference to the fact that Australopithecines were here before Homo habilis.
BE CREATIVE.

The "Information recorded above":

Spoiler

Australopithecines
-4 million to 1 million B.C.
-Found in southern and eastern Africa
-Brain size is 500 cm cubed
-First human like creature to walk upright

Homo habilis
-2.5 to 1.5 million B.C.
-Brain size is 700 cm cubed
-First to make stone tools
-Found in east Africa

Homo erectus
-1.6 million to 30,000 B.C
-Found in Africa, Asia and Europe
-Brain size is 1,000 cm cubed

I'm not that creative, so this whole dialogue thing is diffucult.

[Psychospacecow]

Well, you could have the oldest calling the others noobs, and have belittle the others for their meager intelligence. Could also have erectus as having been around the block, as we made it out of Africa, and have Habilis skin an antelope with his stone knife the whole time. That, or have them all kill each other because their relationships were rather hostile.

[Ghost Nappa]

This is an extra credit question so I'm pretty sure giving me the answer wouldn't be a big deal, unless you want me to do it by myself.
The average speed of sound in water is 1,500 m/s. How long would it take for a sound wave to travel 9,000 m in water?

[Petie]

I'm on my phone and don't feel like switching to the calculator but the answer is (9,000/1,500) seconds.

If you're curious why that works though, it is stated that sound can travel 1,500 meters in 1 second in water so to calculate how long it would take to travel 9,000 meters, you simply take that distance and divide it by the sound's speed. It ties into the dimensional analysis from the other day. In units, you have [distance]/([distance]/[time]). The two distances cancel out leaving you with just the time you're looking for (really, it leaves you with 1/(1/[time]) which simplifies to [time].

And since I typed all of that up, I realized that the answer didn't require a calculator. It's 6 seconds.

[gamemaster1991]

I got a Discussion Question for school. Maybe you guys can help with this:

List three things that a web designer must consider and understand about the purpose or target audience prior to site development. Why do you think each of these is important to a successful plan?

[Combat Lobster]

I got a Discussion Question for school. Maybe you guys can help with this:

List three things that a web designer must consider and understand about the purpose or target audience prior to site development. Why do you think each of these is important to a successful plan?

Let me answer your question with this: Click me

[Lazlo Falconi]

Interesting question... Look up UX design philosophy.

[Ghost Nappa]

“The promises of this world are empty, lacking depth and meaning”

The question is; What do you think this means?
I don't really understand it and it sounded interesting so I wanted to share it here. What do you guys think it means?

[Psychospacecow]

The quote is as it says. Nothing in life is certain, no goal is guaranteed, no man will never lie, no river shall never dry.

---

You are given the following two vectors:
Vector A:10.0 km 60 degrees [N of E]
Vector B: 12.0 km [W]

Add the two vectors using the component method.

What do I do?

[Psychospacecow]

Assuming the acceleration of an object is 5.63 m/s squared, its normal force is 65.5 N, and its mass is 10 kg, how far will a mass travel in 5 seconds assuming there is no friction?

[Petie]

I'm not sure that problem makes sense. First, is the object starting from rest or does it have an initial velocity? Are we assuming it's traveling horizontally across a friction-less surface or is some other kind of motion involved? Is this object not on Earth because a normal force of 65.5 N would mean that the object weighs roughly 6.7 kg under Earth's gravity. And if we're assuming that the 5.63 m/s^2 is actually acceleration due to gravity, it still gives an 11.6 kg object.

All that being said, the formula you're likely going to be using is x = (1/2)at^2, so, plugging in, you get (1/2)(5.63)(5)^2 = 2.815*25 = 70.4 m, assuming that the object starts from rest. If you are not starting from rest, the formula becomes vt+(1/2)at^2 where v = initial velocity, a is still 5.63 m/s^2, and t is 5 seconds meaning your answer would be 5v + 70.4 m. Normal force and mass are irrelevant in this case, given that there is no friction.

[Psychospacecow]

Sorry if its unclear. I tried to phrase it from what I've got so far.
The formula you gave me got the right answer though. My homework is weird in that it provides the answer but wants you to solve for it.

It was
Hannah pulls a 10 kg mass with a force of 65 N at an angle of 30 degrees. Assume there is no friction.
1. Draw a FBD (done)
2. Determine the acceleration (it ended up being 5.63)
3. Determine normal force (was 65.5 N)
4. How far will the mass travel in 5 seconds. (70.4, btw thanks Petie)

I didn't mean for it to be confusing.

Thinking about it, I guess its kind of like the math problems where Stacy's mom buys 670 watermelons and eats 360. lol

[Petie]

No need to apologize. I didn't realize we were at the last step of a multi-step problem. I just thought your physics book (or wherever the problem came from) was very poorly written, haha.

And no problem, glad I could help. I don't have much occasion to do this kind of math any more so it keeps my skills sharp.

[Psychospacecow]

Another question, how do you factor in friction? We haven't really covered that but for some reason the next question says the force of friction equals 25 N.