Science & Mathematics - 7 October 2007

I am checking a freinds homework and cant remember how to do these.
1.Solve: (5x/4)-(5x/7)=(5/28)

2.Solve for y. x + 3y = 9

2007-10-07 05:53:44 · 4 answers · asked by Anonymous in Mathematics

i need this in at atleast in 1 1/2 hours!!!

2007-10-07 05:51:10 · 2 answers · asked by Answerer 2 in Earth Sciences & Geology

Can't get started on this one. Any help would be greatly appreciated. Many thanks!

2007-10-07 05:50:26 · 2 answers · asked by Anonymous in Mathematics

any web sources would be great also...

2007-10-07 05:48:01 · 3 answers · asked by Anonymous in Earth Sciences & Geology

I am doing a project about "Use of Batteries as Power Sources", but I cannot think of anything that is using batteries as HIGH DC power sources or as a back up power for.

1) Can anyone give me more examples of what equipments, nowadays or in the past, use High DC voltage or DC energy. (NOT things about MP3 etc)

For example, 90 V DC would power a vintage valve portable radio.
Car battery would need to step up the voltage from 14V? to ????volt to make a spark for starting an engine, these kinds of things.

2)Can anyone suggest any websites that supply knowledge of what high DC power can do? (better if there are pictures and professional information)

3) Any suggestion for what equipments are needed or would be good if they use DC power in the future?

2007-10-07 05:46:45 · 2 answers · asked by Question Boy 1 in Engineering

How can i speed up the time a little bit, just to make 2 years pass in 2 seconds.

2007-10-07 05:45:37 · 6 answers · asked by fast&furious 2 in Physics

I am suppose to answer this true or false and I say it is false. Pyramids and prisms are totally different from each other structure wise. Right?

2007-10-07 05:45:05 · 2 answers · asked by Jen 4 in Mathematics

When the egg and sperm meet,
When the first heartbeat beats
or
When the first breath is taken?

2007-10-07 05:44:51 · 8 answers · asked by ♥愛♥ 2 in Biology

2007-10-07 05:41:12 · 16 answers · asked by Anonymous in Zoology

2007-10-07 05:39:11 · 7 answers · asked by i wished i lived in nanaimo 1 in Astronomy & Space

I am talking about the black and white cows that are used for milk production, do themales have udders too? or just the females? asking because on the new cartoon back at the barnyard the boy cow has udders?

2007-10-07 05:38:53 · 19 answers · asked by pkw 1 in Zoology

I answered the first part, but I wanted to get you guys' opinion to see if it was correct, and to also show me the answer to the second question. Thank you all!
Here is a link to the questions:
http://www.flickr.com/photo_zoom.gne?id=1506235511&context=photostream&size=o

2007-10-07 05:37:20 · 2 answers · asked by finitemathkid 1 in Mathematics

2007-10-07 05:35:57 · 4 answers · asked by . 1 in Mathematics

what is james watt famous for.This is for my physics homework, the answer has to do with something about energy.Thanks guys!!

2007-10-07 05:32:59 · 4 answers · asked by Anonymous in Engineering

The simple interest formula: P = A / 1+rt ; for r

2007-10-07 05:30:11 · 2 answers · asked by . 1 in Mathematics

A ball thrown horizontally at 25 m/s travels a horizontal distance of 50 m before hitting the ground. From what height was the ball thrown?
m

2007-10-07 05:29:48 · 8 answers · asked by lol83388 1 in Physics

A boat takes 2 hours to travel 30 km down a river, then 7.5 hours to return. How fast is the river flowing?
wrong check mark km/hr

2007-10-07 05:29:17 · 7 answers · asked by lol83388 1 in Physics

As a science fair project, you want to launch an 600 g model rocket straight up and hit a horizontally moving target as it passes 35 m above the launch point. The rocket engine provides a constant thrust of 15.0 N. The target is approaching at a speed of 15 m/s. At what horizontal distance between the target and the rocket should you launch?

2007-10-07 05:26:57 · 3 answers · asked by Jim E 1 in Physics

I cant find the structure anywhere! some help would be apprieciated

2007-10-07 05:26:05 · 3 answers · asked by jujubeans 3 in Chemistry

Sam (75 kg) takes off (from rest) up a 50 m high, 10° frictionless slope on his jet-powered skis. The skis have a thrust of 240 N. He keeps his skis tilted at 10° after becoming airborne, as shown in Figure P6.43. How far does Sam land from the base of the cliff?

2007-10-07 05:26:01 · 1 answers · asked by Jim E 1 in Physics

2007-10-07 05:25:10 · 1 answers · asked by Anonymous in Chemistry

Susan, driving north at 55 mph, and Shawn, driving east at 45 mph, are approaching an intersection. What is Shawn's speed relative to Susan's reference frame?

2007-10-07 05:24:53 · 1 answers · asked by Jim E 1 in Physics

What do you call this bug, and what do you know about it?

http://www.flickr.com/photos/urtica/410539374/

2007-10-07 05:23:32 · 1 answers · asked by Rhouse2007 1 in Zoology

2007-10-07 05:21:15 · 4 answers · asked by Anonymous in Biology

What are the penalties?
History of the drug?
How long is the high?

Thanks in advance!

2007-10-07 05:20:05 · 1 answers · asked by MikeM 2 in Medicine

Calculate the work done (in Joules) when 45.6 g of tin dissolves in excess acid at 1.03 atm and 23deg.C. Assume ideal gas behavoir

Sn(s) + 2H(+)(aq) ---> Sn(2+)(aq) + H2

2007-10-07 05:20:02 · 1 answers · asked by Anonymous in Chemistry

is it a
solid
liquid
gas
please explain your answer
_x_X_x

2007-10-07 05:17:17 · 19 answers · asked by Anonymous in Chemistry

Here is the problem.

8d - ( - 7c - 2d ) = ( 8d - (- 2d ) ) - ( - 7c )

= 8d + 2d - ( -7c )

= 10d - ( - 7c )

= 10d + 7c

Did I work this correctly? I am not sure if I worked the sign changes the right way. Any input would be appreciated.

2007-10-07 05:14:34 · 7 answers · asked by Worldly scholar 1 in Mathematics

I am having trouble understanding how to set up a specific problem. Here it is:

"You drove 56 miles one way on a service call. On the return trip, your average speed was 8 miles per hour greater and the trip took 10 fewer minutes. What was your average speed on the return trip?"

Thanks!

2007-10-07 05:11:53 · 3 answers · asked by lax21222 1 in Mathematics

Solve by using the quadratic formula. 5x^2 – 3x = 1

2007-10-07 05:07:15 · 3 answers · asked by trevor s 2 in Mathematics