Science & Mathematics - 3 October 2007

A block of mass 2.50 kg is pushed 2.80 m along a frictionless horizontal table by a constant 18.0 N force directed 25.0° below the horizontal.
(a) Determine the work done by the applied force.
J
(b) Determine the work done by the normal force exerted by the table.
J
(c) Determine the work done by the force of gravity.
J
(d) Determine the work done by the net force on the block.
J

2007-10-03 13:25:21 · 1 answers · asked by BMac 3 in Physics

2007-10-03 13:23:58 · 3 answers · asked by Anonymous in Mathematics

Two resistances, R1 and R2, are connected in series across a 9 V battery. The current increases by 0.100 A when R2 is removed, leaving R1 connected across the battery. However, the current increases by just 0.050 A when R1 is removed, leaving R2 connected across the battery. What are the two resistances?

2007-10-03 13:23:53 · 3 answers · asked by Hera08 1 in Physics

2007-10-03 13:18:09 · 4 answers · asked by Suzan T 2 in Earth Sciences & Geology

Given that x = 3 * 10^6 and y = 1.2 * 10^9, find the value of each of the following, expressing your answers in standard form.

(i) x^2 - y

2007-10-03 13:17:11 · 1 answers · asked by Anonymous in Mathematics

or as unbiased as possible. looking for any good religion v. science books, and not really sure where to ask. (figured asking in the religious/spirituality section would be pointless!)

personal experience greatly appreciated!

2007-10-03 13:14:28 · 4 answers · asked by Anonymous in Biology

How many grams of Mg metal can be produced in 3.00 h using a current of 47.0 amps to electrolyze molten magnesium chloride?

2007-10-03 13:13:37 · 1 answers · asked by Anonymous in Chemistry

There this question that has been on the quiz for a couple of time..and i miss it all the time. Please help and explain how can i solve these kind of problem.

An adult pass for a country fair cost $2 more than a children pass. When 378 adult and 214 children passes were sold, the total revenue was $2384. Find the cost of an adult pass.

2007-10-03 13:12:38 · 3 answers · asked by yue 1 in Mathematics

I'm doing a science project where I have to make a diorama of oceanic zone but i have no idea how to....my teacher gave the easy ones everyone but when it came to me she always has to give the hardest one!! anways....the kind of information i need is: climate, climatogram, regions, geography,plants, animal,relationships (commensalism, mutualism, and parasitism), and food chain...please tell me any website where i can find all these info..

P.S - if u have any idea how to create a diorama, feel free to share it with me =] all ideas are WELCOME!

2007-10-03 13:12:13 · 1 answers · asked by w00t w00t 1 in Other - Science

2007-10-03 13:11:16 · 4 answers · asked by Anonymous in Biology

Before firing liq. fuel, atomising steam is used to atomised fuel for complete combustion in boilers, why atomising steam temprature reduced with water before it introduced in burner with liq. fuel ? please explain me.

2007-10-03 13:11:09 · 4 answers · asked by amshaikh748 1 in Engineering

There is this really hard homework problem that involves weighted averages. The question is:

A pinapple drink contains 15% pineapple juice. How much pure pineapple juice should be added to 8 quarts of the drink to obtain a mixture containing 50% pineapple juice?

Please tell me the answer and tell me how you solved it!!!

2007-10-03 13:10:40 · 3 answers · asked by charley c 1 in Mathematics

please help me with that question, and how do you know if that is a permutation or a combination?
besides having order matter in a permutation and in a combination order not matter, what is another thing that is significant between them? i just cant tell the difference!

thanks in advance :D

2007-10-03 13:10:02 · 2 answers · asked by doppelganger; 2 in Mathematics

Ok i noe what ur gonna say. That i sould do my own homework and stop asking but i have tried these 2 question like a million times and i cannot figure them out.
Please help

1) Assuming no air resistance, how long does it take a penny to fall if it was thrown down with an initial velocity of 5.0m/s from the CN Tower (553m)?

2) Superwoman is hovering above the ground when a person free-falling goes by her at a terminal velocity of 39 m/s. Unfortunately, the parachute doesn not open. Fortunately, Superwoman is around. If it takes her 1.9s to realize the person is in distress, what must her acceleration be if she is to catch the parachutist just before she hits the ground 1000m below.?

Please help
U dont have to jus tell me the answers... even if u jus help me understand them it would be much appreciated. If u do show me how to get the answer.. Please show the steps and explain. Thank You in Advance.

2007-10-03 13:07:31 · 4 answers · asked by Anonymous in Physics

I think that g's of acceleration are just a/9.8, right? Not sure how to set up this problem...

You read about a car accident in the newspaper. A car traveling at 70 km/h collided with a concrete bridge support. The front end of the car was compressed 0.92 m, and the car came to a complete stop within this distance.

How many g's of acceleration did the occupant of the car experience?

I feel like I need to know his mass or something, but no other info is given??

2007-10-03 13:07:25 · 4 answers · asked by lilrnblover86 4 in Physics

For this problem I tried completing the square and then used trig substitution, but it doesn’t seem right because it forced me to have the lower limit of integration be arctan(2/3), which does not have one of the known exact values.

1. x dx / [x^2 + 4x + 13] (from 0 to 1; definite integral)

(which reads as x in the numerator, dived by x squared plus 4x plus 13 in the denominator).

2007-10-03 13:06:21 · 2 answers · asked by Ryan_1770 1 in Mathematics

Before firing liq. fuel, atomising steam is used to atomised fuel for complete combustion in boilers, why atomising steam temprature reduced with water before it introduced in burner with liq. fuel ? please explain me.

2007-10-03 13:06:08 · 1 answers · asked by amshaikh748 1 in Engineering

can someone tell me how to do problems like . . .

1.-3g + 9 = 15g - 9

2.4x + 27 = 3x + 34

3.10y = 2y - 6y + 7

4. 4 + 6x - 9x = 3x

5.13x + 8 + 8x = -9x - 22

6.5x - 3x + 4 = 3x + 8

these are so hard i have no clue what to do.

2007-10-03 13:04:09 · 8 answers · asked by Mike 2 in Mathematics

the landing speed of a space shuttle is 347 km/h.if a shuttle is landing at a angle of 15 degrees with respact to the horizontal,what are the horizontal and the vertical componets of its velocity? THANK YOU SO MUCH...

2007-10-03 13:01:35 · 1 answers · asked by Regina 1 in Physics

what tempeture will the mixture turn when you mix baking soda and vinegar together, what actions will take place?

2007-10-03 13:01:20 · 2 answers · asked by LaLa K 1 in Chemistry

1.
(a)Calculate the work done in lifting a 520 N barbell 2.4 m above the floor
(b)What is the potential energy of the barbell when it is lifted to this height?

2.
Suppose an automobile has 3100 J of kinetic energy.
(a)When it moves at twice the speed, what will be its kinetic energy?
(b)What's its kinetic energy at three times the speed?

2007-10-03 13:00:33 · 3 answers · asked by atlz1anonly 1 in Physics

Please xplain your answer. your help is graetly appreciated :)

2007-10-03 12:54:58 · 6 answers · asked by MiCk 2 in Physics

my wife has been seeing our family doctor since a work accident.the doctor reiazed her pain and prescribed her lori-tabs,for 10 months even though the wife sees her monthly.the doctor also made her sign a realease stating if she got addicted,that it releases her.now catch 22 here, the doctor then wrote her another prescription for the same amount of doseage,this has been like 3 months ago,now the doctor is saying the wife is abusing them,but isn,t the doctor suppose to know what and how many prescription she writes out for her patiants.and now she is cutting her off all togather ,which is like cold turkey.does anyone think that this is negelence on her part,and is there or should there be a recourse her.thanks for any information

2007-10-03 12:43:01 · 8 answers · asked by indm45 3 in Medicine

2007-10-03 12:40:46 · 1 answers · asked by New York 1 in Physics

2007-10-03 12:39:44 · 6 answers · asked by Anonymous in Earth Sciences & Geology

Alright...I know it sounds crazy, but im deathly afraid of these things.
theyre always in my house, not mosquitos.
what are they called??
http://www1.istockphoto.com/file_thumbview_approve/1888193/2/istockphoto_1888193_bug_on_the_wall.jpg

does anybody know the scientific name/the most common name for it?

most appreciated. =]

2007-10-03 12:39:40 · 5 answers · asked by Em 2 in Zoology

Electrons (m = 9.109x10-31 kg) are accelerated from rest theough an electric potential difference of 305 V. They then enter a uniform magnetic field B = 0.200 T that is perpendicular to their direction of motion.

2007-10-03 12:39:11 · 1 answers · asked by Kelly 1 in Physics

I'm wondering because when i was working, there was a nest of them and we had to call the exterminator.

2007-10-03 12:38:32 · 2 answers · asked by Anonymous in Zoology

2007-10-03 12:37:15 · 12 answers · asked by ? 6 in Astronomy & Space

a ball is launched at 30angle above horizontal. what launch speed is required so that the kiwi will land in basket 35 meters distant across level ground

2007-10-03 12:36:06 · 2 answers · asked by alkesh831 2 in Physics