Friday

August 26, 2016
Total # Posts: 900

**physics(URGENT!!!!!)**

8.01xers Can anybody help with the falling ruler. I submission left(
*December 9, 2013*

**physics(URGENT!!!!!)**

A ruler stands vertically against a wall. It is given a tiny impulse at θ=0∘ such that it starts falling down under the influence of gravity. You can consider that the initial angular velocity is very small so that ω(θ=0∘)=0. The ruler has mass m= ...
*December 8, 2013*

**physics I'M STUCK PZL HELP**

A ruler stands vertically against a wall. It is given a tiny impulse at θ=0∘ such that it starts falling down under the influence of gravity. You can consider that the initial angular velocity is very small so that ω(θ=0∘)=0. The ruler has mass m= ...
*December 8, 2013*

**physics Classical Mechanics**

Consider a rocket in space that ejects burned fuel at a speed of vex= 1.5 km/s with respect to the rocket. The rocket burns 8 % of its mass in 280 s (assume the burn rate is constant). (a) What is the speed v of the rocket after a burn time of 140.0 s? (suppose that the rocket...
*December 8, 2013*

**physics Classical Mechanics**

Hi, guys! What's about doppler shift? Can u tell me formulas?
*December 8, 2013*

**physics(URGENT!!!!!)**

Anonymous can u explain c onemore time?
*December 8, 2013*

**Physics Classical Mechanics**

@kumar can you explain a)
*December 8, 2013*

**Chemistry**

What is the lattice energy of NaI? Use the given information below. Heat of formation for NaI = -288.0 kJ/mol Heat of sublimation for Na = 107.3 kJ/mol Ionization energy for Na = 496.0 kJ/mol Bond dissociation energy for I2 = 149 kJ/mol Electron affinity of I = -295.0 kJ/mol ...
*November 22, 2013*

**Science**

1.- B 2.- D 3.- C 4.- C
*November 15, 2013*

**Chemistry**

Heisenberg's uncertainty principle can be expressed mathematically as Δx*Δp = h/4π, where Δx and Δp denote the uncertainty in position and momentum respectively and h is Planck's constant. What would be the uncertaintry in the position of a ...
*November 10, 2013*

**Chemistry**

What is the mass of a fly in grams if its de Broglie wavelength is 1.545e-31 m when it is traveling at a velocity of 3.605 m/s
*November 10, 2013*

**Chemistry**

Hydrogen exhibits several series of line spectra in different spectral regions. For example the Lyman series (nf = 1 in Balmer-Rydberg equation) occurs in the ultraviolet region while the Balmer (nf = 2) series occurs in the visible range and the Paschen (nf = 3), Brackett (...
*November 10, 2013*

**Chemistry**

Hydrogen exhibits several series of line spectra in different spectral regions. For example the Lyman series (nf = 1 in Balmer-Rydberg equation) occurs in the ultraviolet region while the Balmer (nf = 2) series occurs in the visible range and the Paschen (nf = 3), Brackett (...
*November 10, 2013*

**Physics**

elbow raises a 1200 N piano a distance of 5 meters using a set of pulleys. elbow pulls in 20.0 meter of rope while exerting a force of 340 N. a) what is the work output? b) what is work input c) what is the mechanical advantage of this machine? d) what is the efficiency of ...
*November 3, 2013*

**physics**

mass of passenger is 90 kg and mass of scale is 40 kg what is scale reading inside an elevator moving at 7.8 m/s2 upward? does the mass of the scale affect the scale reading ?
*November 3, 2013*

**Geomentry**

prove the statement Angle ABD is a right angle and Angle CBE is a Right Angle and prove Angle ABC is Congruent to Angle DBE
*October 27, 2013*

**Chemistry**

The energy (in joules) of an electron energy level in the Bohr atom is given by the expression: En = -2.179 x 10-18/n2 J where n is the principal quantum number for the energy level. What is the frequency in Hz of the electromagnetic radiation absorbed when an electron is ...
*October 21, 2013*

**Chemistry**

What volume of a liquid having a density of 4.55 g/cm3 is needed to supply 10.47 grams of that liquid? Answer in cm3.
*October 12, 2013*

**English**

thank you :)
*September 29, 2013*

**English**

Don't know how to recognize it but i know what it means. It is something that is ironic or sarcastic. Right?
*September 29, 2013*

**English**

really need help on this question it is worth 5 marks. The question is: Explain how "A Thankless Experience" is a satire with support with direct reference to the essay. The short essay is called A Thankless Experience by Stephen Lautens' it is on the internet ...
*September 29, 2013*

**A Thankless Experience**

I did study these but can't seem to start on a sentence. I dont know what sentences from the essay are satire. If i could get started on one i might be able to understand.
*September 28, 2013*

**A Thankless Experience**

I really need help on this question it is worth 5 marks. The question is: Explain how "A Thankless Experience" is a satire with support with direct reference to the essay. The short essay is called A Thankless Experience by Stephen Lautens' Thank you :)
*September 28, 2013*

**English**

Story: A Thankless Experience Author: Stephen Lautens Question: Describe the diction that Lautens uses in "A Thankless Experience"? Describe Lautens tone in "A Thankless Experience"? Help will be appreciated :)
*September 25, 2013*

**english A Thankless Experience Questions**

Abstract words present qualities or ideas that cannot be felt by the senses. They are often general words, as opposed to concrete words which express something more tangible. Truth, honor and happiness are all abstract words, while aroma, stone and fire are concrete words. ...
*September 25, 2013*

**books **

Thank you please help me on my other posts please and thank you help will be appreciated
*September 25, 2013*

**books **

I could not please help pleaseeee :)
*September 25, 2013*

**books "A Thankless Experience" Short Essay Help**

This is the story: A Thankless Experience by Stephen Lautens. The story is on the internet. jiskha does not allow me to post the url The question is: Provide two examples of figurative language used by Lautens in his essay and describe the effect of each example. Please help ...
*September 25, 2013*

**books (A thankless experience)**

Thank you Ms. Sue
*September 24, 2013*

**books (A thankless experience)**

Explain whether Lautens' essay is written formally or informally, referring to examples from the essay for support. The short essay is on the internet called A thankless experience by Stephen Lautens. I can not post the url because jiskha does not allow it.
*September 24, 2013*

**books(short essay)**

Yes this is the short essay. Thanks so much
*September 24, 2013*

**books(short essay)**

Describe the sentence structure Stephen Lautens uses in "A Thankless Experience". Support your view with examples from the essay. This is the story: A Thankless experience by Stephen Lautens this story is on the internet I was about to post the url but jiskha does ...
*September 24, 2013*

**Reading**

Thank you
*September 16, 2013*

**Reading**

It's from the Journey's text book.
*September 16, 2013*

**Reading**

Double Dutch 5th grade reading.
*September 16, 2013*

**Reading**

What was the order in which all the girls learned double dutch?
*September 16, 2013*

**Chemistry**

A sheet of aluminum (Al) foil has a total area of 2.119 ft2 and a mass of 2.714 g. What is the thickness of the foil in millimeters? (Density of Al = 2.699 g/cm3? I got 5.108*10^-4 cm but that is wrong. (2.714g)/(2.699g/cm^3)/(2.119ft^2) * 1ft/30.48cm = 5.108*10^-4 cm
*September 15, 2013*

**math**

Thanks for your help.
*September 11, 2013*

**math**

How would I show my work for this answers?
*September 11, 2013*

**math**

how do you write 3.08 as a fraction?
*September 11, 2013*

**econmics**

Suppose the price of widgets rises from $7 to $9 and consumption of widgets falls from 25 widgets a month to 15 widgets. Calculate your price elasticity of demand of widgets. What can you say about your price elasticity of demand of widgets? Is it Elastic, Inelastic, or ...
*September 10, 2013*

**Math**

How do you know if a steam and leaf display is uniform, unimodal or bimodal?
*September 5, 2013*

**Math**

One advantage of a _____________ is that the actual data values are retained in the graphical display of the data. A) Pie chart B) Dot plot (This one?) C) Histogram D) boxplot If we want to discuss any gaps and clusters in a data set, which of the following should not be ...
*September 5, 2013*

**Geometry**

The length of one side of an isosceles triangle is two times the base b. This length is equal to (8b - 12),in. What is the value of b?
*September 4, 2013*

**Math**

A two-player game is played with two piles of stones, with sizes m,n. On a player's turn, that player can remove any positive integer number of stones from one pile, or the same positive integer number of stones from each pile. A player loses when they are unable to take a...
*August 12, 2013*

**Math (Combinatorics) **

How many ways to rearrange 9 a's, 2 b's, and 2c's so that we never see bc and both b's always appear before both c's?
*July 30, 2013*

**calculus (please help steve)**

Evaluate ∬(x^2+y^2)^2/(x^2y^2) dx dy over the region common to the circles x^2+y^2=7x and x^2+y^2=11y.
*July 26, 2013*

**calculus (please help steve)**

ok, thanks!
*July 25, 2013*

**calculus (please help steve)**

But we are taking a double integral. This would be finding a volume.
*July 25, 2013*

**calculus (please help steve)**

Evaluate ∬(x^2+y^2)^2/(x^2y^2) dx dy over the region common to the circles x^2+y^2=7x and x^2+y^2=11y.
*July 25, 2013*

**calculus**

Evaluate ∬(x^2+y^2)^2/(x^2y^2) dx dy over the region common to the circles x^2+y^2=7x and x^2+y^2=11y.
*July 25, 2013*

**Calculus-HELP!!!**

wolfram alpha says (s^2+8)/(s^3+16s)
*July 25, 2013*

**calculus**

valuate ∬(x^2+y^2)^2/(x^2y^2) dx dy over the region common to the circles x^2+y62=7x and x^2+y^2=11y
*July 25, 2013*

**calculus**

Evaluate ∬R 1/sqrt(x^2+y^2) dx dy, where R is the region bounded by y≥0 and x^2−x+y^2≤0.
*July 25, 2013*

**calculus**

ok, thanks
*July 25, 2013*

**calculus**

could you give me a bit help on how to proceed if I were to use a volume integral?
*July 25, 2013*

**calculus**

Let V be the volume of the region bounded by x^2+y^2≥z^2, z≥0 and x^2+y^2+z^2≤1. What is the value of ⌊100V⌋?
*July 25, 2013*

**physics**

What is the wind speed in m/s required to keep a great white shark suspended in midair during a summer day on the California beach? Details and assumptions Model the shark as a horizontal cylinder 6 m long and 1 m in diameter. The air is at a pressure of 1 atm and a ...
*July 24, 2013*

**Data Structures and Algorithms**

545
*July 24, 2013*

**math**

Let S be the set of {(1,1), (1,−1), (−1,1), (1,0), (0,1)}-lattice paths which begin at (1,1), do not use the same vertex twice, and never touch either the x-axis or the y-axis. Let Sx,y be the set of paths in S which end at (x,y).For how many ordered pairs (x,y) ...
*July 23, 2013*

**math**

A token is placed on the leftmost square in a strip of four squares. You are allowed to move the token left or right along the strip by sliding it a single square, provided that the token stays on the strip. How many ways can the token be moved such that after 15 moves, it is ...
*July 23, 2013*

**physics**

integral (1+cos 2T) dT = T + sinTcosT so (2/Pi)v integral (1+cos 2T) dT from 0 to pi/2 = 1 ?
*July 23, 2013*

**physics**

so we would solve to get 66.51?
*July 23, 2013*

**physics**

so how would we apply this 3v/2 into your original equation rho * 2 r L v^2 = 1000(9.8)(pi r^2)(L) ?
*July 23, 2013*

**physics**

how did you get the volume of air that hits the shark per second?
*July 23, 2013*

**physics (fluids)**

If a object of radius 3 cm is attached to the ground in a 3 m deep sea, what is the vertical force in N with which the water (density = 1000 kg/m^3) presses on it?
*July 22, 2013*

**calculus (hint?)**

f(x) is a twice differentiable function such that f(2x)=f(x+5)+(x−5)^2 What is f''(x)?
*July 21, 2013*

**calculus**

If f(x)=∫ (from -x to x) cos(t)/(1+e^t) dt and x=asin(77/85), then the absolute value of f′(x)−f(x) can be expressed as a/b, where a and b are coprime positive integers. What is the value of a+b?
*July 20, 2013*

**calculus**

I would still like help as to how I would proceed. That is why I still ask for the answer.
*July 20, 2013*

**calculus**

However, I am still confused as to how I would proceed.
*July 20, 2013*

**calculus**

so what is the answer to the question?
*July 20, 2013*

**calculus**

If f(x)=∫ (from -x to x) cos(t)/(1+e^t) dt and x=asin(77/85), then the absolute value of f′(x)−f(x) can be expressed as a/b, where a and b are coprime positive integers. What is the value of a, and what is the value of b?
*July 20, 2013*

**calculus**

f(x) and f′(x) are continuous, differentiable functions that satisfy f(x)=x^3+4x^2+∫ (from 0 to x)(x−t)f′(t) dt. What is f′(5)−f(5)?
*July 20, 2013*

**calculus (point me in the right direction please?)**

but how would you get f(5)?
*July 19, 2013*

**calculus (point me in the right direction please?)**

f(x) and f′(x) are continuous, differentiable functions that satisfy f(x)=x^3+4x^2+∫(from 0 to x)(x−t)f′(t) dt. What is f′(5)−f(5)?
*July 19, 2013*

**calculus (point me in the right direction please?)**

thank you steve!
*July 18, 2013*

**calculus (point me in the right direction please?)**

Let V be the volume of the three-dimensional structure bounded by the region 0≤z≤1−x^2−y^2. If V=a/bπ, where a and b are positive coprime integers, what is a+b?
*July 18, 2013*

**physics**

114 mm Hg = 15198.75 pascals 16.0 cm^2 = 0.0016 m^2 P=F/A 15198.75=F/0.0016 F=24.318 newtons
*July 18, 2013*

**calculus**

he volume of the solid obtained by rotating the region bounded by x=(y−2)^2 and y=x about the x-axis has the form N/2π. What is the value of N?
*July 18, 2013*

**calculus**

oops! Thanks for the help
*July 18, 2013*

**calculus**

alright, so i got that f'(x)=4x^3-76x^2+4ax =4x(x^2-19x+4a) since this must never equal 0, it must have no solutions. Therefore, x must not be 0 and x^2-19x+4a must not be 0. For that to occur, 289-16a<0, so a > 18.0625. Can you please check me work? Sorry for ...
*July 18, 2013*

**calculus**

How many positive integers a (<1000) are there such that the function f(x)=x^4−76/3x^3+2ax^2 has no local maxima?
*July 18, 2013*

**calculus**

Are you just going to assume that any problem I ask for help on is from "Brilliant"?
*July 18, 2013*

**calculus**

How do you know anyways?
*July 18, 2013*

**calculus (could you help point me in the right direction?)**

could someone please point me in the right direction?
*July 18, 2013*

**calculus**

Let V be the volume of the three-dimensional structure bounded by the region 0≤z≤1−x^2−y^2. If V=a/bπ, where a and b are positive coprime integers, what is a+b?
*July 18, 2013*

**math**

If (x+2)f(2−x)+(2x+1)f(2+x)=1 for all real values of x, then f(18)=a/b, where a and b are coprime positive integers. What is the value of a+b?
*July 18, 2013*

**calculus**

How many integer values of a are there such that f(x)=x^+ax^2+8ax+25 has no local extrema?
*July 18, 2013*

**calculus**

A 3-dimensional structure is obtained from rotating the parabola y=x^2 about the y-axis. Each second, 2π units^3 of water is being poured into the structure from the top. When 8π units^3 of water has been poured in the structure, the instantaneous change in water ...
*July 18, 2013*

**calculus**

no, i think that ∫[0,2] π((4y)^2-(2y^2)^2) dy is 256/15π
*July 18, 2013*

**calculus**

i believe its bounded from y=0 to y=2
*July 18, 2013*

**calculus**

The area bounded by the curve 2y^2=x and the line 4y=x is rotated around the y-axis. The volume of the resulting structure can be expressed as V=a/bπ, where a and b are coprime positive integers. What is the value of a+b?
*July 18, 2013*

**calculus**

The area bounded by the curve 2y^2=x and the line 4y=x is rotated around the y-axis. The volume of the resulting structure can be expressed as V=a/bπ, where a and b are coprime positive integers. What is the value of a+b?
*July 17, 2013*

**calculus**

A 3-dimensional structure is obtained from rotating the parabola y=x^2 about the y-axis. Each second, 2π units^3 of water is being poured into the structure from the top. When 8π units^3 of water has been poured in the structure, the instantaneous change in water ...
*July 17, 2013*

**math calculus**

The volume of the solid obtained by rotating the region bounded by y=x^2−2x and y=x about the line y=9, has the form a/bπ, where a and b are positive coprime integers. What is the value of a+b?
*July 17, 2013*

**physics**

no its wrong!
*July 17, 2013*

**physics**

A clock is made out of a disk of radius R=10 cm which is hung by a point on its edge and oscillates. All of a sudden, a circular part right next to the hanging point of radius R/2 falls off, but the clock continues oscillating. What is the absolute value of the difference in s...
*July 17, 2013*

**physics**

Telephoto lenses allow one to "zoom in" on distant objects, making them bigger. A particular telephoto lens consists of a combination of two thin lenses having focal lengths of f1=20 cm and f2=−8 cm, respectively. The lenses are separated by a distance of d=15 ...
*July 17, 2013*

**math (please help steve)**

Brilli the ant randomly placed a token into a square on a 2×100 chessboard according to a probability distribution P. The token is then moved uniformly at random to one of the horizontally, vertically, or diagonally adjacent squares. The probability that the token is in ...
*July 17, 2013*

**math**

Brilli the ant is considering the complexities of a 5-dimensional universe. She wants to count the number of integer points that are distance sqrt(n) away from the origin. Let Tn be the set of ordered 5-tuples of integers (a1,a2,a3,a4,a5) such that a1^2+a2^2+a3^2+a4^2+a5^2=n....
*July 17, 2013*