Science & Mathematics - 18 October 2007

can you show your solution please? I'm stuck on 2 of my homework questions.

41. In an old-fashioned amusement park ride, passengers stand inside a 5.0 m diameter hollow steel cylinder with their backs against the wall. The cylinder begins to rotate about a vertical axis. Then the floor on which the passengers are standing suddenly drops away! If all goes well, the passengers will "stick" to the wall and not slide. Clothing has a static coefficient of friction against steel in the range 0.6 to 1.0 and a kinetic coefficient in the range 0.4 to 0.7. A sign next to the entrance says "No children under 30kg allowed." What is the minimum angular velocity, in rpm, for which the ride is safe?

2. A 500g ball moves in a vertical circle on a 102cm long string. If the speed at the top is 4.0m/s, then the speed at the bottom will be 7.5m/s
a) What is the ball's weight?
b. What is the tension in the string when the ball at the top?
c. Tension in the string when the ball at bottom?

2007-10-18 08:48:44 · 1 answers · asked by Anonymous in Physics

i saw something in the sky and i didnt no wt it was nd mi m8 said it was the araura! we also saw death written in the sky when we were talking about death and he also said that was part of the aurora, was that true?

2007-10-18 08:48:16 · 14 answers · asked by steph g 1 in Astronomy & Space

A physics student playing with an air hockey table (a frictionless surface) finds that if she gives the puck a velocity of 3.80 m/s along the length(1.75 m) of the table at one end, the puck has drifted 2.50 cm to the right but still has a velocity component along the length of 3.80m/s. She correctly concludes that the table is not level and correctly calculates its inclination from the above information. What is the angle of inclination?

2007-10-18 08:46:08 · 2 answers · asked by selece_wingard 1 in Physics

for a candle

2007-10-18 08:44:54 · 6 answers · asked by Anonymous in Chemistry

This one has me baffled - I've been asked to write a balanced chemical equation with state symbols for the reaction of propan-1-ol with sodium.

As the produced sodium propoxide is ionic I assume that it cannot be a liquid at room temperature. Now, when we did this experiment, no solid ppt. was formed so i assume that the propoxide is in solution. But it's not aqueous is it? There was never any water? That rules out (aq)

Help!

2007-10-18 08:43:08 · 3 answers · asked by Angharad T 1 in Chemistry

What volume of oxygen gas at 320 K and 680 torr will react completeley with 2.50 L of NO gas at the same temperature and pressure?
2NO(g) + O2(g) 2NO2(g)

2007-10-18 08:42:17 · 3 answers · asked by PiNk-PrInCeSs 3 in Chemistry

2007-10-18 08:40:00 · 6 answers · asked by Anonymous in Chemistry

what are 2 polygons other than a square and a rectangle whose reflections are identical to the original. Show how the reflectin of a triangle can be the same as the original.

I dont understand this question, Help! Thanks in advance!!!!!!!!

2007-10-18 08:39:19 · 2 answers · asked by Brittany l 2 in Mathematics

a certain number n has facters of 15 and 10. what is the fewest total number of positive factors that n cna have??

the odds of an event happening successfully are expressed as a:b, where a:b is the ratio of the probability of a succesfullly event to the probability of an unsuccesful event. The odds of roling a 5 on an unfair die are 1:3. What is the probability of rolling a 5 with this die? express you answer as a percent

2007-10-18 08:37:40 · 1 answers · asked by John the beast 2 in Mathematics

2007-10-18 08:36:43 · 20 answers · asked by Victoria S 1 in Paranormal Phenomena

Which of the following pairs of atoms would you expect to combine chemically to form an ionic compound?

a. Li and S
b. O and S
c. Al and O
d. F and Cl
e. I and K
f. H and N

Can you explain this to me? I'm having trouble understanding it!! Thanks so much!

2007-10-18 08:36:42 · 4 answers · asked by Angel D 1 in Chemistry

2007-10-18 08:36:26 · 9 answers · asked by MIKE M 1 in Mathematics

a. about the same as Earth's

b. much greater than Earth's

c. much smaller than Earth's

d. zero

2007-10-18 08:34:25 · 9 answers · asked by vicwso 1 in Astronomy & Space

what do whales actually do

2007-10-18 08:33:36 · 12 answers · asked by loopy 1 in Zoology

2007-10-18 08:32:53 · 9 answers · asked by vicwso 1 in Astronomy & Space

I will appreciate your help, and I ned someone to explain me how can I attached some graphs to this questions.
Question 1)
a) What is the constant of the spring?
b) From your graph (force vs. distance), does the spring follow Hooke’s law?
c) Do you think that it would always follow Hooke’s law no matter how far you stretched it?
d) Why is the slope of your graph positive, while Hooke’s law has a minus sign?
Question 2)
Compare the work you measured to stretch the spring to 10 cm, 20 cm, and the maximum stretch to the stored potential energy predicted by this experiment. Should they be similar?
Stretch
10 cm 20 cm Max. Stretch
Integral (during pull) (N∙m) 0.0865 0.25 0.752
∆ PE (J)

2007-10-18 08:31:49 · 2 answers · asked by Natiphy2007 1 in Physics

ok.. I think if someone can show me step for step how to do this I can figure out the rest of the problems

3^(2x) + 3^(x) - 2 = 0

please help!!!

2007-10-18 08:27:52 · 3 answers · asked by me 3 in Mathematics

I need assistance in solving this - step by step ?

100 mL of M Sucrose Solution - what is the formula weight of sucrose and how much sucrose is needed to make 1 L of 1M sucrose?
-then-
how much is needed to make 100mL?

2007-10-18 08:27:51 · 4 answers · asked by LydonPuggles 2 in Chemistry

2007-10-18 08:25:55 · 2 answers · asked by jane 2 in Astronomy & Space

Which of the following pairs of elements will not form ionic compounds?

a. Sulfur and Oxygen
b. Sodium and Calcium
c. Sodium and Sulfur
d. Oxygen and Chlorine

Could you please explain this to me? I'm having trouble understanding this thing. Thanks.

2007-10-18 08:25:27 · 6 answers · asked by Angel D 1 in Chemistry

the picture was on the front page this week of a rare white tiger or leopard or some large cat eating a birthday cake

2007-10-18 08:24:48 · 1 answers · asked by Anonymous in Zoology

2007-10-18 08:23:23 · 1 answers · asked by sun_240 1 in Chemistry

Title explains all.

2007-10-18 08:16:26 · 6 answers · asked by Anonymous in Astronomy & Space

Okay, so, if a mint decides to replace it's pure silver coin with a sandwich coin that is 1/2 silver and 1/2 copper and the volume of the coin (both the old style and the new) is O.24cm cubed, what is the difference in grams between the old coin and the new one?

Btw, the density of silver is 10.5 g/cm cubed and the density of copper is 9.0 g/cm cubed.

I'm just not sure how to get the density of an object made of two different elements and subsequently get the mass from knowing the density and the given volume.

I just need help understand how to work this problem, I don't need an answer.

Thanks

2007-10-18 08:15:53 · 6 answers · asked by Anonymous in Mathematics

OK my daugther and i have one mostof her sheets and we have a couple of questions that she doest understand and i dont have a clue so please help me:)

here we go...

1,what is the abundance of aluminium

2,why were only 7 metals known untill approx 1800 ad

3, why do metals excist as ores(explain in a bit of detail please)


thanks :)

2007-10-18 08:15:34 · 1 answers · asked by kt 2 in Chemistry

I thought this could be fun for paranormal enthusiast and skeptic alike. This is a YouTube video that the creator really really REALLY wants people to believe is actual footage of a shadow ghost. His video is quite popular and has tons of comments, all of which are mysteriously uncritical of the video. However, there is at least one dead giveaway it's a fake.

When you view it, view it full screen. Watch for the shadow to appear and to move across the door. Did you spot the visual clue that gives it away?

http://youtube.com/watch?v=evNHMcrW7R0

2007-10-18 08:15:30 · 13 answers · asked by John 7 in Paranormal Phenomena

I have to make a weird "artsy" video for class,

so I'm squirting shampoo/lotion/other crap on top of a piece of stretched-out saran wrap, over the camera .. and then coming up with some lame, "spiritual" meaning for it. :/ ugh.

At the end, I want to scrape it all into a bowl & microwave it.

Will it explode? (if there's nail polish remover/hairspray in it?)

I dont want to set my dorm on fire.

2007-10-18 08:14:41 · 3 answers · asked by Anonymous in Chemistry

My science teacher gave us notes and it put this in them and I dont know if it is true.

2007-10-18 08:13:39 · 7 answers · asked by Taylor O 1 in Biology

Don't you think that driving 4-7 miles in 3 years a little too little? I mena, of course they are not Bugattis, but 4 miles is just seems like too slow. A reasonable distace would be 50-100 miles. Keep in mind, that's during 3 years!


Why do you think they are that slow?

2007-10-18 08:13:26 · 7 answers · asked by rockability 1 in Astronomy & Space

I'm having difficulty with this question:

Two solutions, 0.10L of 0.12M NaCl, and 0.23L of 0.18M MgCl2, are mixed together. What volume (in mL) of a 0.20M solution of AgNO3 is needed to precipitate all the Cl- ion as AgCl?

I'm not sure how I need to go about doing this.

2007-10-18 08:10:51 · 5 answers · asked by K Z 2 in Chemistry