Science & Mathematics - 28 November 2007

A car traveling at 48ft/sec decelerates at a constant 4feet per second squared.

Let denote f(x)the position function seconds after the decelerating process started. Then . f(0)=0
What is f'(0)? Answer:

What is f''(x)? Answer:

Use the above information to find f'(x)

Then, use f(0)=0 to find f(x)

How many feet does the car travel before coming to a complete stop?

Answer:

2007-11-28 16:21:24 · 4 answers · asked by scott b 1 in Mathematics

Doppelgangers are supposed to look exactly like you (that's what I heard) so why would mine be a guy? I saw it when my mom and dad were fighting one day when I was younger (I'm currently 16). I felt like I couldn't move and then I saw myself (as a guy) in the kitchen holding a knife. I actually felt like I was holding one. What does that mean? A male doppelganger? Thanks for reading.

2007-11-28 16:20:24 · 13 answers · asked by xxDisenchantedxx 2 in Paranormal Phenomena

2007-11-28 16:14:14 · 3 answers · asked by Anonymous in Earth Sciences & Geology

at what point did you find proof there was no spirit? Did you find proof of this somewhere? Or is it your belief that there is no spirit? At last check there is no scientific proof for or against the existance of the spirit or an intelligent creator. I dont want to hear negative proving negative answers. I want to really hear how you came to your conclusion without any proof either way. Because without proof, then what you think becomes a belief. And to have a belief, one must have faith. Outside of a few responders, very few are respectful of those who do believe in spirits and ghosts. Yet you expect us to believe everything we know of came as a result of a big bang that cannot be proven, the "something from nothing theory".

2007-11-28 16:13:45 · 14 answers · asked by nuff said 6 in Paranormal Phenomena

Please help me identify which reaction occurs in the Diet Coke and Mentos experiment.

chemical?
physical?
or
exothermic?

please help!

2007-11-28 16:08:53 · 23 answers · asked by Tami N 2 in Chemistry

please don't bother because i allready know the answer.
i just want to know why do we forget great men of our time
about whome will only be able to read in the future but we can touch them allready put them in our fillings just for probable references?have you ever wished to e-mail him?

2007-11-28 16:07:14 · 6 answers · asked by Anonymous in Astronomy & Space

2007-11-28 16:05:05 · 7 answers · asked by lalaworld 1 in Chemistry

Four people are to be selected at random from a group of four couples. In how many ways can this be done, given the following conditions?
a. there are no restriction.. i got this to be.. 8 C 4 = 70
b. the group must have at least one couple..
c. each couple must be represented in the group.

i don't know how to do b and c... can anyone help

2007-11-28 16:05:05 · 7 answers · asked by linh 1 in Mathematics

Suppose that a string has a length L. What is the largest possible wavelength of a standing wave that can be supported by the string?

2007-11-28 16:03:14 · 2 answers · asked by Anonymous in Physics

??

2007-11-28 16:00:56 · 3 answers · asked by Anonymous in Mathematics

An airplane is flying horizontally with speed 800 km/h (222 m/s) when an engine falls off. Neglect air resistance, and assume it takes 20 s for the engine to hit the ground.

How high is the airplane? in meters

How far horizontally does the engine travel while it falls? in meters

2007-11-28 15:57:45 · 1 answers · asked by joe s 1 in Physics

You have to use less than 10 pieces. It must be rigid. It does not have to hold water. It CANNOT involve a union. No bending. No welding. It has to be done with standard plumbers tools. All pipe must be the same diameter. No reverse threading. I'm stumped. But I know a guy who swears it can be done. Do you knowit?

2007-11-28 15:57:36 · 2 answers · asked by Leroy J 3 in Engineering

2007-11-28 15:57:31 · 8 answers · asked by Anonymous in Earth Sciences & Geology

Trig problem I need help with.
How can I prove this expression. Please help me!!

2007-11-28 15:57:13 · 2 answers · asked by anthony c 2 in Mathematics

Estimate the pressure exerted on a floor by the following.
(a) a 46 kg model standing momentarily on a single spiked heel (area = 0.06 cm2)

2007-11-28 15:56:42 · 3 answers · asked by Anonymous in Physics

Let the &'s be radicals because i can't find how to type it in my computer.

^3&320& + ^3&1250&
-----------------------------------
2 ^3&5&

How can i get rid of the radical on the bottom?

2007-11-28 15:55:50 · 1 answers · asked by basketcase 2 in Mathematics

2007-11-28 15:55:09 · 1 answers · asked by aileen d 1 in Biology

Assume: The length of the athlete's arm is included in the length given for the chain below.

An athlete whirls a 6.81 kg hammer tied to the end of a(n) 1.3 m chain in a horizontal circle. The hammer moves at a rate of 1.47 rev/s.

a) What is the centripetal accelaration of the hammer? (in m/s^2)

b) What is the tension in the chain? (in N)

2007-11-28 15:53:01 · 1 answers · asked by ? 2 in Physics

The problem is..... cos(sqrt[x])/sqrt[x]

I have tools that can show me the final answer, but I would like to know how it is done step by step. I dont see the point in knowing the answer without actually knowing how to get there.

2007-11-28 15:52:03 · 6 answers · asked by Anonymous in Mathematics

A motor having an efficiency of 88% operates a crane having an efficiency of 42%. With what constant speed does the crane lift a 410kg crate of machine parts if the power supplied to the motor is 5.5kW?

Power=Force*Velocity
so
5.5=velocity*force
how do you find force?

2007-11-28 15:50:38 · 5 answers · asked by Anonymous in Physics

How do you prove the diagonals of a rhombus are perpendicular?

On this problem I have determined the points should be (0,0),
(a,0) (b,c) and (b+a,c). I have also found the slopes of the diagonals to be c/b+d and c/(b-d). But I don't what to do after this. I think you would prove that c^2 = a^2 - b^2 using cross multiplication on the slopes, but why would you want to prove this? I thought that opposite reciprocal slopes signify perpendicular lines; does this signify that too?

2007-11-28 15:50:00 · 2 answers · asked by Nathan 3 in Mathematics

Seems like there are two off-shoots of Jose Silva's Silva Mind Control Method. Am planning a first level seminar and can't decide which one to go with - as in a) More effective b) More authentic?
Need to make a decision before 3rd December 2007.

2007-11-28 15:49:16 · 8 answers · asked by masooma27 1 in Parapsychology

Jake, Mel, and Annie went mountain biking on Mammoth Mountain. Each biker took a different trail. They biked for a total of 10 hours and 10 minutes. Mel biked 2/3 as long as Jake and Annie biked 30 minutes less than Jake did. How long did each of them bike?

This is the question. I know it can be solved with Guess and Check, but I need the algebraic way, and FAST!
Please don't tell me to solve it myself, because I have no idea for the technique. Please post the walkthrough and the once-over of the question on your answer.
Thank you SO much for answering this question! First decent answer posted with a clear description and why you did so and so, will be best answer.
May the best person win!
(I need the answer in a day, due Friday)

2007-11-28 15:48:11 · 6 answers · asked by Seashells 2 in Mathematics

2007-11-28 15:47:49 · 23 answers · asked by chris o 2 in Paranormal Phenomena

How do you suppose a nearby (but not direct) lightning strike could damage the tuner in your TV, which was turned on? (i.e. Why is it a good idea to unplug TVs and computers when an electrical storm is very close?)

2007-11-28 15:47:25 · 2 answers · asked by Anonymous in Other - Science

affect how fast it will germinate. I have done 6 trials. for each trial there were 3 cups i tested. 1s got no water, 2s got water once a week, and 3s got watered ever day. I realized that groups 2 and 3 germinated between 4-6 days. I got the data, but how do i make a data table for that? and how and what kind of graph would i make?

2007-11-28 15:46:49 · 1 answers · asked by Escape 1 in Mathematics

The asteroid Ceres has a mass of 6.769*10^20 kg and a radius of 478.3 km.

a.) What is g on the surface? The value of gravitational constant is 6.67259*10^-11.

b.) How mush would an 85.4 kg astronaut weigh on this asteroid? (in units of N)

2007-11-28 15:46:07 · 2 answers · asked by ? 2 in Physics

2007-11-28 15:42:29 · 3 answers · asked by Gail C 1 in Biology

2007-11-28 15:42:01 · 2 answers · asked by subrat p 1 in Mathematics

2007-11-28 15:41:47 · 22 answers · asked by cspanik21 1 in Astronomy & Space