Science & Mathematics - 18 October 2007

it's for homework, thanks.

2007-10-18 04:53:43 · 10 answers · asked by Anonymous in Mathematics

Consider the sequence given by...

u1 = −0.3, un+1 = un + 0.7 (n = 1, 2, 3, . . .).

(i) State what type of sequence this is.

(ii) Write down the first four terms of the sequence.

(iii) Find a closed form for the sequence.

(iv) Use the closed form from part (iii) to find the value of n when un = 36.1.

would the answers be this :

(i) it is an arithmetic sequence

(ii) the final first four terms are -0.3, 0.40, 1.10, 1.80

(iii) the closed form is: un= -0.3 + (n-1) 0.7

(iv) n = 53

are this right ????

2007-10-18 04:52:51 · 4 answers · asked by Anonymous in Mathematics

A new record for running the stairs of the Empire State Building was set on February 3, 2003. The 86 flights, with a total of 1576 steps, was run in 9 minutes and 33 seconds. Consider a scenario where a man ran up 1600 steps of the Empire State Building in 10 minutes and 59 seconds. If the height gain of each step was 0.20 m, and the man's mass was 61.0 kg, what was his average power output during the climb? Give your answer in both watts and horsepower.

Help if you can please.

2007-10-18 04:49:11 · 3 answers · asked by Imagine 1 in Physics

A net force changes the velocity of a 10 kg object by 1m/s every second. How long will it take this net force to change the velocity of a 100 kg object by 1 m/s?

2007-10-18 04:46:13 · 1 answers · asked by chiropteran 1 in Physics

An astrophysicist working at an observatory is interested in finding clouds of hydrogen in the galaxy. Usually hydrogen is detected by looking for the Balmer series of spectral lines in the visible spectrum. Unfortunately, the instrument that detects hydrogen emission spectra at this particular observatory is not working very well and only detects spectra in the infrared region of electromagnetic radiation. Therefore the astrophysicist decides to check for hydrogen by looking at the Paschen series, which produces spectral lines in the infrared part of the spectrum. The Paschen series describes the wavelengths of light emitted by the decay of electrons from higher orbits to the n=3 level.

2007-10-18 04:45:26 · 2 answers · asked by Anonymous in Physics

2007-10-18 04:45:11 · 2 answers · asked by christiansareawesome 4 in Mathematics

made their cocoons. Do I need to set them outside or will they be able to do their transformation indoors?

2007-10-18 04:43:10 · 5 answers · asked by Chickenfarmer 7 in Zoology

2007-10-18 04:41:56 · 3 answers · asked by Anonymous in Physics

At what minimum speed must a roller coaster be traveling when upside down at the top of a circle if the passengers are not to fall out. The radius of curvature is 7.54 metres. The mass of the passenger is 72.00 kg. [Answer in km/h]

A. 8.6 km/h
B. 30.9 km/h
C. 16.3 km/h
D. 13.3 km/h
E. 74.9 km/h

2007-10-18 04:40:50 · 4 answers · asked by Anonymous in Physics

Any formula that you can use to prove your answer?

2007-10-18 04:40:12 · 1 answers · asked by charm 1 in Physics

A 2 kg mass is attached to a string which is attached to a second mass 1 kg The string passes over a pulley and the two masses both hang down. They are released from rest. How long does it take for each to move 0.9 metres?
A. 0.52 s
B. 1.35 s
C. 0.74 s
D. 0.25 s
E. 0.17 s

2007-10-18 04:39:24 · 2 answers · asked by Anonymous in Physics

2+ 5/x =7

2007-10-18 04:38:59 · 7 answers · asked by Anonymous in Mathematics

2007-10-18 04:36:30 · 5 answers · asked by Carmen R 1 in Geography

1/x^2 + 3/y^2 - 5/2xy

2007-10-18 04:35:21 · 2 answers · asked by Anonymous in Mathematics

A shopper buys three oranges and five lemons for $10.26, while a second shopper buys four lemons and six oranges for $11.16. What is the price of each fruit?

2007-10-18 04:32:35 · 5 answers · asked by Snoopy Baby 1 in Mathematics

2007-10-18 04:31:50 · 2 answers · asked by tootybug31 1 in Geography

What is an electromagnetic wave? Name four types of electromagnetic radiation other than visible light

2007-10-18 04:29:57 · 4 answers · asked by Anonymous in Physics

Please.. and thank you!

2007-10-18 04:28:27 · 3 answers · asked by Anonymous in Mathematics

For example, in NO3- I don't understand why its charge is -1.

2007-10-18 04:25:58 · 3 answers · asked by Victor A 1 in Chemistry

Describe the Doppler Effect in details with illustrations.

2007-10-18 04:24:59 · 4 answers · asked by Anonymous in Astronomy & Space

Determine the wavelength of a light wave traveling through a vacuum if its frequency is 3.50 x 1014 Hz.

2007-10-18 04:22:06 · 4 answers · asked by Anonymous in Astronomy & Space

a). If a tree falls in the forest and no one is around to hear it, is there sound?

b). If an astronaut on the moon dropped a hammer, would there be sound? Explain.

c). How do astronauts communicate with each other and mission control?

2007-10-18 04:19:07 · 8 answers · asked by Anonymous in Astronomy & Space

1) a boat can go 9 km downstream in 45 mins. and return upstream in an hour. find the speed of the boat in still water and the speed of the current

2) the total time taken to travel x km at 30 km/h is 2 1/2 hours. the time taken to travel x km at 15 km/h and y km at 45km/h is 4 hour and 20 mins. find x and y

2007-10-18 04:14:20 · 2 answers · asked by javv>>> 2 in Mathematics

Ok the big bang its the beginning of all, but How , where and who started the big bang.

2007-10-18 04:14:06 · 19 answers · asked by José A 2 in Astronomy & Space

A particular race car can cover a quarter mile in 6.8 seconds, starting from a standstill. If acceleration is constant how many g's does the driver experience? If the combinded mass of the driver and race car is 455 kg what is the horizontal force exerted on the tires? in N

2007-10-18 04:13:24 · 2 answers · asked by matt c 1 in Physics

The problem I'm working on states:
Objects with masses of 120 kg (m1) and a 420 kg (m2) are separated by 0.310 m (m3).
(a) Find the net gravitational force exerted by these objects on a 50.0 kg object placed midway between them.
[The answer I found is 4.1642E-5]
(b) At what position (other than infinitely remote ones) can the 50.0 kg object be placed so as to experience a net force of zero?
___ m from the 420 kg mass

To solve B, would I set the net gravitational force equal to zero? ((Gm1m3)/r^2) + ((Gm2m3)/r^2) = 0, and solve for r?

2007-10-18 04:12:09 · 2 answers · asked by Bill 1 in Physics

Why do people must agonize themselves with Manual Computations? We are in a advanced technological era. Calculators (Scientific) are commonly used in the American land. Manual Computations slows down the process of computing in numerical algorithms and It is time-wasting. Calculators speeds up the process. Therefore the difference is not only in the difficulty in the process but in time. Time really matters. Would rather waste your neurons away or use it. What are your findings? Pls. try not to put answers that are baloney. What are your observations. Should we use machines or our brains? Skeptics are welcome.

2007-10-18 04:09:47 · 6 answers · asked by Kyle J 6 in Mathematics

-Application of maxima and minima
1) A closed box with square base is to have a volume of 2000 in. The material for the top and the bottom of the box is to cost 3 cents per sq.in and the material for the sides is to cost 1.5 cents/in². Estimate to analytically the dimension of the box so that the total cost of the material is least.

2007-10-18 04:08:14 · 3 answers · asked by miaka 1 in Mathematics

Thanks, I need this help for real. Algebra is not my strong point, I am struggling.

2007-10-18 04:07:09 · 4 answers · asked by ♥ ღAngelicaღ♥ 2 in Mathematics

Solve |x| =1 (that's all it says)

How do I do this? I believe the answer is -1 and 1, but I need to explain how I got this answer.

2007-10-18 04:05:25 · 3 answers · asked by Anonymous in Mathematics