Science & Mathematics - 2 November 2007

does ayone have any idea?

2007-11-02 11:58:20 · 5 answers · asked by wik 2 in Astronomy & Space

The speed of a stream is 5mph. A boat travels 5 miles upstream in the same time it takes to travel 15 miles downstream. What is the speed of the boat in still water?

2007-11-02 11:53:53 · 9 answers · asked by batty_starr 2 in Mathematics

10 points to whoever explains it the best=]

2007-11-02 11:53:45 · 1 answers · asked by onetreehunny 4 in Biology

If In An Inner Product Space = for all x, show that u = v

2007-11-02 11:52:55 · 2 answers · asked by Anonymous in Mathematics

A 2.67 kg block slides down a frictionless plane, from rest, with an acceleration of 5.48009 m/s^2. What's the block's speed after travelling 2.1 m along the incline? Answer in m/s

I tried using unit analysis to figure it out and got
v=(distance x acceration)^1/2 = 3.392372319 m/s but the computer says its wrong?

I don't know if I am even on the right track. Please help!

2007-11-02 11:52:00 · 4 answers · asked by Anonymous in Physics

Block A has mass 1.00kg , and block B has mass 3.00kg . The blocks are forced together, compressing a spring S between them; then the system is released from rest on a level, frictionless surface. The spring, which has negligible mass, is not fastened to either block and drops to the surface after it has expanded. Block B acquires a speed of 1.20m/s .

What is the final speed of block A?
How much potential energy was stored in the compressed spring?

Please and thank you.

2007-11-02 11:50:43 · 1 answers · asked by brandon patrick 1 in Physics

9604 aint right

2007-11-02 11:43:37 · 8 answers · asked by Anonymous in Mathematics

A space station shaped like a giant wheel has a radius 96 m and a moment of inertia of 4.96 108 kg·m2. A crew of 150 lives on the rim, and the station is rotating so that the crew experiences an apparent acceleration of 1 g. When 100 people move to the center of the station for a union meeting, the angular speed changes. What acceleration is experienced by the managers remaining at the rim? Assume that the average mass of each inhabitant is 65.0 kg.
____m/s2

2007-11-02 11:41:08 · 1 answers · asked by stars1234 2 in Physics

2007-11-02 11:40:38 · 3 answers · asked by Neo Tarantula 2 in Engineering

In the picture below R1=2.00Ω and R2=4.00Ω. What value of R3 maximizes the dissipation rate in resistance 3? I worked it all out using Kirchoff’s laws and I got R3 = 10/7Ω. I would like to know if first this is correct and second what would happen if R2 is switched from 4.00Ω to 5.00Ω. I would like to see some work with 5.00 Ω, b/c the answer I keep getting is wrong.

http://www.lowellphysics.org/beta/resources/CH27/Problems/c27x27_11.xform_files/nw0394-n.gif

2007-11-02 11:38:35 · 1 answers · asked by Anonymous in Physics

The weight W of an aluminum flatboat varies directly with the length L of the boat. If a 13-foot boat weighs 234 pounds, then what is the weight of a 12-foot boat?

2007-11-02 11:37:13 · 11 answers · asked by batty_starr 2 in Mathematics

there is a bus with 7 girls, each girl carries 7 bags, inside each bag is 7 cats, every cat has 7 kittens, all cats have 4 legs, how many legs are on the bus... i need the answer to get a password to open an email attatchment... god do i need help..lol

2007-11-02 11:36:20 · 9 answers · asked by Anonymous in Mathematics

I have a problem that reads the following:

A rectangular tetrahedron has edges 36 units in length. What is the altitude of the tetrahedron? Give your answer in simplest radical form x sqrt y.

This is supposed to be a challenging problem, and though I'm in honors math, I haven't learned about these shapes. Please don't just give me the answer. Help to point in the right direction.

Thank you so much!

2007-11-02 11:36:03 · 2 answers · asked by Anonymous in Mathematics

I heared that if you paint a styrofoam ball it will disinigrate. But I have to color one for a project. how do i do it?

2007-11-02 11:35:16 · 3 answers · asked by punkmonk713 2 in Other - Science

How many moles of H+ ions are present in 1.25L of .075M HNO3?

2007-11-02 11:30:51 · 3 answers · asked by burgler09 5 in Chemistry

If you were traveling in any type of vehicle, could you in any way, keep up with the sun?
Could you follow the sun fast enough to where it would always be daylight?
I was wondering about this and it's really driving me crazy!
Please answer!

2007-11-02 11:30:12 · 13 answers · asked by vote4pedro0529 1 in Astronomy & Space

The half-life of palladium-100 is 4 days. after 12 days a sample of palladium-100 has been reduced to a mass of 1 mg. what was the initial mass (in mg) of the sample?
________________________

what is the mass 7 weeks after the start?________________

2007-11-02 11:23:55 · 7 answers · asked by star baller 360 5 in Mathematics

2007-11-02 11:22:20 · 8 answers · asked by !!Whoopie!! 2 in Mathematics

The morning after a winter ice storm in Dallas, a 1400kg automobile going west on Chestnut Street at 35.0 km/h collides with a 2800kg truck going south across Chestnut Street at 50.0 km/h .
What is the magnitude and direction of their velocity after colliding?

2007-11-02 11:21:54 · 2 answers · asked by brandon patrick 1 in Physics

Two questions:
1. calculate the expected change in temperature for 4.5 g of NH4NO3 dissolved in 100.0 mL of H20. Assume that the calorimeter absorbs no heat. (ie. Ccal=0)

2. Calculate the change in temperature for 4.50 g of CaCl2 dissolved in 90.0 mL of H20. Assume that the calorimeter absorbs no heat (ie. Ccal=0)

2007-11-02 11:20:11 · 1 answers · asked by Anonymous in Chemistry

5.00 mL of 0.250 M HClO4 diluted to 30.0 mL

2007-11-02 11:19:10 · 3 answers · asked by JTOWN 2 in Chemistry

2007-11-02 11:18:50 · 4 answers · asked by Anonymous in Mathematics

Maybe herbs etc.

2007-11-02 11:17:45 · 4 answers · asked by Anonymous in Medicine

2007-11-02 11:17:30 · 11 answers · asked by RRMCPJ6 2 in Mathematics

2H2 + 2 O2 ---> 2 H2O
Zn(s) + H2SO4(aq) ----> ZnSO4(aq) + H2(g)
H2O(l)+ NH3 ---> NH4 + OH
Cl2 + 2KBr ---->Br2 + 2 KCl

2007-11-02 11:15:21 · 2 answers · asked by burgler09 5 in Chemistry

After meiosis, are the chromosomes in each of the 4 sperm cells created identical or not?

My guess is that they are all different.

Help plz?

2007-11-02 11:11:18 · 2 answers · asked by Anonymous in Biology

Glycerol, C3H8O3, is a substance used extensively in the manufacture of cosmetics, foodstuffs, antifreeze, and plastics. Glycerol is a water-soluble liquid with a density of 1.2656 g/mL at 15°C. Calculate the molarity of a solution of glycerol made by dissolving 80.000 mL glycerol at 15°C in enough water to make 300.00 mL of solution.

2007-11-02 11:10:29 · 2 answers · asked by JTOWN 2 in Chemistry

A 2.60-m-long, 340 kg steel beam extends horizontally from the point where it has been bolted to the framework of a new building under construction. A 75.0 kg construction worker stands at the far end of the beam. What is the magnitude of the torque about the point where the beam is bolted into place?

2007-11-02 11:09:53 · 3 answers · asked by rochesmk 2 in Physics

2007-11-02 11:05:38 · 4 answers · asked by batty_starr 2 in Mathematics

Not asking for answers per say, just help getting the answers. Don't tell me to do my own homework because I did. I'm just double checking to make sure I followed the steps correctly.

http://img159.imageshack.us/img159/7733/01cl8.png

2007-11-02 11:04:35 · 3 answers · asked by Anonymous in Mathematics