Friday

August 28, 2015
Total # Posts: 5,011

**Math**

How many ways can you arrange the order of 4articles on a shelf?please explain why it is 4 x3x2x1,thanks
*November 4, 2013*

**Physics problem**

An object with a mass of 100kg is dropped from an 80 meter high building and leaves an impression in the ground of 15cm. A.What is the time needed to hit the ground? B. What is the speed of the object when it hits the ground? C. What is the coefficient of the friction between ...
*November 1, 2013*

**Physics problem **

An object with a mass of 100kg is dropped from an 80 meter high building and leaves an impression in the ground of 15cm. A.What is the time needed to hit the ground? B. What is the speed of the object when it hits the ground? C. What is the coefficient of the friction between ...
*November 1, 2013*

**Math- urgent**

One more than 3 times a number is the same as 5 times the number, decreased by 15. Find the number. • Assign the variable • Write an equation • Solve equation
*October 30, 2013*

**stats**

The population (in millions) and the violent crime rate (per 1000) were recorded for 10 metropolitan areas. The data are shown in the following table. Do these data provide evidence to reject the null hypothesis that ƒÏ = 0 in favor of ƒÏ ‚ 0 at...
*October 30, 2013*

**history **

I'm having a debate about gay marriage. & I'm arguing that people should have the right to marry who they please because church & state are separate & the constitution grants people rights, including marriage rights. If my opponent says then if everyone has rights, why...
*October 30, 2013*

**University of Belize**

5. A 0.500 g sample of a BaCl2•2H2O/Na2SO4 salt mixture, when mixed with water, filtered, and dried, produced 0.225 g of BaSO4. The Na2SO4 was determined to be the limiting reactant. a. Calculate the mass, in grams, of Na2SO4 in the mixture. b. Calculate the mass, in ...
*October 29, 2013*

**Physics**

On a cloudless day, the sunlight that reaches the surface of the earth has an intensity of about 1.2 103 W/m2. What is the electromagnetic energy contained in 6.4 m3 of space just above the earth's surface?
*October 28, 2013*

**US History**

How did immigration change after 1890?
*October 27, 2013*

**General Physics 2**

Type A dead battery is charged by connecting - PHYSICS HELP? in google search and you'll find a question similar to this on July 17, 2011 good luck
*October 27, 2013*

**physics**

I'm thinking to just divide 632 days by 87.1 days to determine the half-life
*October 24, 2013*

**physics**

If the physical half-life of sulfur-35 is 87.1 days, and the biologic half-life in the testicle is 632 days, what is its effective half-life in this organ? I know i have to find the time and then the half-life. But im having trouble finding the time A(t)=Ao x e ^ (-0.693) (t...
*October 24, 2013*

**Math**

v-7/5=2 What does v equal? Please show all work.
*October 24, 2013*

**Physics**

F incline= mg sin θ F incline = (4.7 kg) (9.81 m/s^2) sin (26) F incline = 20.21 N = 21 N Check to see at the back of the book if this is the right answer. If not go over the formula sheet and the problems in the book and so you'll realize the answer
*October 24, 2013*

**English Literature-Critical Thinking**

Animals should serve as models for us. They are gentle, cooperative, and family-oriented creatures who fight mainly over territory and mates and rarely kill one another. Humans being engage in group warfare and slaughter one another by millions. In fact, we stop behaving like ...
*October 24, 2013*

**Math - Urgent**

2/3x+1/2x=5/6+2x What does x equal? Please show all work.
*October 23, 2013*

**Math - Urgent**

3-2/9b=1/3b-7 What does b equal? Please show all work
*October 22, 2013*

**Math - Urgent**

3-2/9b=1/3b-7 What does b equal? Please show all work.
*October 22, 2013*

**Math - Urgent**

Yes, that is what I meant. Sorry for the confusion. Thank you.
*October 22, 2013*

**Math - Urgent**

3/4x+2=7+1/3x What does x equal? Please show all work.
*October 22, 2013*

**Math- Urgent**

Thank you.
*October 21, 2013*

**Math- Urgent**

Thank you I was confused because I had -8 as an original answer. How would you work 4x-9=6x-13?
*October 21, 2013*

**Math- Urgent**

2e= 4e-16 What does e equal? Please show all work.
*October 21, 2013*

**MATHS**

In 2006, the digits in Perry's age were the same as the digits in Laura's age, but in reverse order. In 2005, Perry was twice Laura's age. What is the difference between Perry's and Laura's ages?
*October 21, 2013*

**MATHS**

Please help! Pedro and Alice raced two model trains along two straight tracks. Pedro's train travelled 7.5 cm every minute. Alice's train travelled 7.5 cm every second. How many centimeters had Alice's train travelled when Pedro's train had travelled 2.75 ...
*October 21, 2013*

**Physics**

To win the game, a place kicker must kick a football from a point 40 m (43.744 yd) from the goal, and the ball must clear the crossbar, which is 3.05 m high. When kicked, the ball leaves the ground with a speed of 23 m/s at an angle of 30.9◦ from the horizontal. The ...
*October 19, 2013*

**Physics**

A ﬁreman, 34.9 m away from a burning building, directs a stream jet of water from a ground level ﬁre hose at an angle of 44.2◦ above the horizontal. If the speed of the stream as it leaves the hose is 60.5 m/s, at what height will the stream of water strike...
*October 19, 2013*

**Physics**

To win the game, a place kicker must kick a football from a point 40 m (43.744 yd) from the goal, and the ball must clear the crossbar, which is 3.05 m high. When kicked, the ball leaves the ground with a speed of 23 m/s at an angle of 30.9 ◦ from the horizontal. The ...
*October 19, 2013*

**Physics**

A five-sided object, whose dimensions are shown in the figure, is placed in a uniform magnetic field. The magnetic field has a magnitude of 0.72 T and points along the positive y direction. Determine the magnetic flux through each of the five sides. picture can be found on ...
*October 19, 2013*

**physics**

yes that's right, thank you very much.
*October 19, 2013*

**physics**

A cardiologist uses an ultrasound scanner with an operating frequency of 3.5 MHz that can detect Doppler frequency shifts as small as 0.1 kHz. What is the smallest flow velocity detectable with this device? Two frequencies are given so I know I have to convert the units but ...
*October 19, 2013*

**physics**

okay, one plane is flying north, straight up and the wind blows the plane east [right]. This is almost similar to pythagorean theorem. My guess is to use x^2 + y^2 = z^2. But im pretty sure there's a formula for this in the first or two chapters of the physics book. Look ...
*October 19, 2013*

**physics**

There is a relationship between momentum and energy KE = 1/2mv^2 p = mv m = p/v KE = 1/2 (p/v)v^2 KE = 1/2 pv From wiki answers The relation between kinetic energy is proportional to the square of velocity. Momentum is directly proportional to velocity. If the momentum of an ...
*October 19, 2013*

**Physics**

Find the potential energy when x = 0 or x = -1 Then using this energy then find speed using KE = 1/2mv^2 m = 1 kg
*October 18, 2013*

**Math- Urgent**

1/4 w=13 What does w equal? Please show all work.
*October 16, 2013*

**Math- Urgent**

Thank you.
*October 16, 2013*

**Math- Urgent**

Thank you. I have one more question. 1/4 w=-13
*October 16, 2013*

**Math- Urgent**

15=y+24 What does y equal? Please show all work.
*October 16, 2013*

**History**

Those are all good ideas. Thank you!!
*October 14, 2013*

**History**

My text doesn't say specifically anything, but I have to infer. For Portugal I found four things, but for Spain I only thought of that they had strong armies, they wanted to find the Spice Islands, and that they wanted to spread Christianity to non-Christian areas.
*October 14, 2013*

**History**

What are some factors that are responsible for the emergence of Portugal and Spain as the most dominant powers of Europe during the early 16th century? Make sure to have multiple factors for each country.
*October 14, 2013*

**math**

Anyone can help me on this qns? The Fourier series expansion for the periodic function,f(t) = |sin t|is defined in its fundamental interval. Taking π = 3.142, calculate the Fourier cosine series approximation of f(t), up to the 6th harmonics when t = 1.09. Give your ...
*October 13, 2013*

**maths**

make x the subject 1/4wxy-p=k
*October 13, 2013*

**Maths**

t (1/8x+p)=m Make x the subject
*October 13, 2013*

**Fourier Series**

A periodic function f(t), with period 2π is defined as,f(t) = c for 0 < t < πf(t) = -c for -π < t < 0where c = 1.4, Taking π = 3.142, calculate the Fourier sine series approximation up to the 5th harmonics when t = 1.63. Give your answer to 3 ...
*October 13, 2013*

**Physics**

I really don't get why I am getting this question wrong? Please can you explain to me how to do this question step by step so that I can understand it please? :( i have been stuck on this question for quite a while now. Determine the stopping distances for an automobile ...
*October 11, 2013*

**Physics**

I really don't get why I am getting this question wrong? Please can you explain to me how to do this question step by step so that I can understand it please? :( i have been stuck on this question for quite a while now. Determine the stopping distances for an automobile ...
*October 11, 2013*

**Physics**

I really don't get why I am getting this question wrong? Please can you explain to me how to do this question step by step so that I can understand it please? :( i have been stuck on this question for quite a while now. Determine the stopping distances for an automobile ...
*October 11, 2013*

**Physics**

I really don't get why I am getting this question wrong? Please can you explain to me how to do this question step by step so that I can understand it please? :( i have been stuck on this question for quite a while now. Determine the stopping distances for an automobile ...
*October 11, 2013*

**Science**

What is the relationship between the number of gas particles and pressure. Are these two variables directly proportional or do they vary inversely?
*October 9, 2013*

**algebra**

Can you help me solve for like terms: x - 14y + 3x - 1 2 - 10x - 3 + y 19x - 3y - 37 - y
*October 9, 2013*

**Macolm X**

2011–2012 seasons, Patrice Bergeron entered a game against the Ottawa Senators with a plus/minus rating of +20. In the game, which Boston won 4–3; Bergeron was on the ice for one of his team's qualifying goals as well as all three qualifying goals by the Senators...
*October 7, 2013*

**Chemistry**

Calculate the molarity of a solution made by adding 28.2 mL of concentrated ammonia (28.0 % by mass, density 0.880 g/mL) to some water in a volumetric flask, then adding water to the mark to make exactly 500 mL of solution. (It is important to add concentrated acid or base to ...
*October 7, 2013*

**Physics**

A track star in the long jump goes into the jump at 12 m/s and launches herself at 20.0° above the horizontal. How long is she in the air before returning to Earth? (g = 9.81 m/s2)
*October 6, 2013*

**Math: Pre-calculus**

A rancher wants to build a rectangular pen with an area of 180 . Let W be the width of the pen and L be the length of the pen. a) Find an equation for the perimeter P in terms of W and L . b) Use the given area to write an equation that relates W and L . c) Find the pen ...
*October 6, 2013*

**Math- urgent**

What is (6.91 x 10-2 power) + (2.4 x 10-3 power) ? Express your answer in scientific notation.
*October 3, 2013*

**Physics**

. A package sitting on a shelf is knocked off. The velocity of the box just before it hits the floor is 8.5 m/s. Calculate the height of the shelf using; A displacement/velocity/acceleration equation Conservation of energy and hence show that these two methods produce the same...
*October 2, 2013*

**Physics**

A particular task exposes the operator to alpha radiation at an average dose of 200 ìGy each time the task is performed. If the company needs the task performed once per day over a 250-day working year and the maximum occupational dose limit is 20mSv per year, how many ...
*October 1, 2013*

**physics**

This is an example question which I have the answer to but can not seem to get the same answer through my workings, any help with the equation would be great. A particular task exposes the operator to alpha radiation at an average dose of 200 ìGy each time the task is ...
*October 1, 2013*

**Math**

Emma is 5 years older than 6 times beth's age. If Emma is 29 years old how old is Beth?
*October 1, 2013*

**check my work on derivatives**

Can someone check my work? So, I took the derivative of (1-x^2)/((1+x^2)^2) I used the quotient rule ((2x((1+x^2)^2)-2((1+x^2)^2)(2x)(1-x^2))) / ((1+x^2)^4) Then I simplified it (2x+2x^2 - 4x((1+x^2)^2)(1-x^2)) /((1+x^2)^4) Then I simplified by factoring out some numbers 2x(x^...
*September 30, 2013*

**physics**

A motorist travelling at 82 km/hr is being chased by a police car at 121 km/hr. If the police car starts from 4.0 km back, how long does it take to catch the motorist? Leave time in hours.
*September 30, 2013*

**geometry**

what is a concave polygon using the classify and differentiate method
*September 26, 2013*

**Chemistry**

A volume of 60.0mL of aqueous potassium hydroxide (KOH ) was titrated against a standard solution of sulfuric acid (H 2 SO 4 ). What was the molarity of the KOH solution if 25.7mL of 1.50 M H 2 SO 4 was needed? The equation is 2KOH(aq)+H 2 SO 4 (aq)¨K 2 SO 4 (aq)+2H ...
*September 26, 2013*

**History (chronological order)**

1,2,4,3
*September 25, 2013*

**Physics 2 College Level**

A cylinder is closed at both ends and has insulating walls. It is divided into two compartments by an insulating piston that is perpendicular to the axis of the cylinder as shown in Figure a. Each compartment contains 1.00 mol of oxygen that behaves as an ideal gas with γ...
*September 17, 2013*

**grammar fast plz**

Well then it will be just freshmen. So you would say "...YOU, the freshmen-class of 2017.
*September 17, 2013*

**Chemistry**

We did a flame test today to see what substances produce what colors when burned. Can you please explain... Why each of the different elements have a different atomic emission spectrum? Would the flame tests be useful for detecting individual elements present in a mixture of ...
*September 17, 2013*

**Math urgent**

Oh I understand now. Thank you so much!
*September 16, 2013*

**Math urgent**

Thank you! Could you please show your work to how you got to 1/10? It would be easier to explain to my class.
*September 16, 2013*

**Math urgent**

What is 4.1 repeating written as a fraction? I don't know if it should be written over 100 or over 10.
*September 16, 2013*

**Chemistry**

Orange light has a frequency of 4.8 x 10^14 s^ -1. What is the energy of one quantum of orange light?
*September 16, 2013*

**Economic**

Who has an unlimited checking account with the US Treasurer that enables them to write all the checks they want without regard to having funds in the bank?
*September 14, 2013*

**Science**

Helium doesn't react with any other substance. Is it accurate to say that helium has no chemical properties? Explain. Please help because I'm not sure of the answer. Thank you.
*September 13, 2013*

**Science**

*IM SORRY I MEANT SCIENCE FOR THE SUBJECT.
*September 13, 2013*

**History**

Helium doesn't react with any other substance. Is it accurate to say that helium has no chemical properties? Explain. Please help because I'm not sure of the answer. Thank you.
*September 13, 2013*

**AP Calculus**

I asked this yesterday and someone answered. but i didn't understand the explanation.. Two circles of radius 4 are tangent to the graph of y^2=4x at the point (1,2). Find equations of these two circles. I got (x-1)^2+(y-2)^2=16 and (x-4.36)^2+(y+1.36)^2=16
*September 12, 2013*

**Math**

plug in 4 for x, and -3 for y. 4-4(-3)/2 4+12/2 16/2 8
*September 12, 2013*

**math**

At 4 pm, Jack who is 6 ft tall cast a shadow that is 4 1/2 ft long. At the same time, a nearby free cast a shadow that is 12 ft long, how tall is the tree?
*September 12, 2013*

**AP Calculus**

A projectile fired upward from ground level is to reach a maximum height of 1,600 feet. What is its initial velocity?
*September 11, 2013*

**AP Calculus**

Two circles of radius 4 are tangent to the graph of y^2=4x at the point (1,2). Find equations of these two circles. I found the derivative of y^2=4x, but i don't know what to do next!
*September 11, 2013*

**Computer Science**

The array represents a map with coins, and the integers represent a row and column location of a coin gatherer. The gatherer is greedy and lazy when deciding to which adjacent location (either up, down, left, right) to move next. It’s greedy because it moves to the ...
*September 8, 2013*

**Physics**

A firefighter 41.8m away from a burning building, directs Zach stream of water from a ground level fire hose at an angle of 33.0 degrees above the horizontal . If the speed of the streams it leaves the hose is 42.7m/s, at what height will the stream of water hit the building
*September 8, 2013*

**Physics**

Suppose a single electron orbits about a nucleus containing two protons (+2e), as would be the case for a helium atom from which one of the two naturally occurring electrons is removed. The radius of the orbit is 2.65 10-11 m. Determine the magnitude of the electron's ...
*September 8, 2013*

**Physics**

A circular surface with a radius of 0.058 m is exposed to a uniform external electric field of magnitude 1.49 104 N/C. The electric flux through the surface is 74 N · m2/C. What is the angle between the direction of the electric field and the normal to the surface?
*September 8, 2013*

**Physics**

In the rectangle in the drawing, a charge is to be placed at the empty corner to make the net force on the charge at corner A point along the vertical direction. What charge (magnitude and algebraic sign) must be placed at the empty corner? (the rectangle has +3 uC charges in ...
*September 8, 2013*

**Physics**

Suppose a single electron orbits about a nucleus containing two protons (+2e), as would be the case for a helium atom from which one of the two naturally occurring electrons is removed. The radius of the orbit is 2.65 10-11 m. Determine the magnitude of the electron's ...
*September 8, 2013*

**Math**

A projectile is fired with an initial velocity of v0 feet per second. The projectile can be pictured as being fired from the origin into the first quadrant, making an angle O with the positive x-axis. If there is no air resistance, then at t seconds the coordinates of the ...
*September 8, 2013*

**Physics**

Suppose a single electron orbits about a nucleus containing two protons (+2e), as would be the case for a helium atom from which one of the two naturally occurring electrons is removed. The radius of the orbit is 2.65 10-11 m. Determine the magnitude of the electron's ...
*September 6, 2013*

**Physics**

A circular surface with a radius of 0.058 m is exposed to a uniform external electric field of magnitude 1.49 104 N/C. The electric flux through the surface is 74 N · m2/C. What is the angle between the direction of the electric field and the normal to the surface?
*September 6, 2013*

**physics**

A is the bottom left corner. The empty corner is the top right corner.
*September 6, 2013*

**physics**

In the rectangle in the drawing, a charge is to be placed at the empty corner to make the net force on the charge at corner A point along the vertical direction. What charge (magnitude and algebraic sign) must be placed at the empty corner? (the rectangle has +3 uC charges in ...
*September 6, 2013*

**Physics**

Two point charges are fixed on the y axis: a negative point charge q1 = -26 µC at y1 = +0.21 m and a positive point charge q2 at y2 = +0.30 m. A third point charge q = +8.5 µC is fixed at the origin. The net electrostatic force exerted on the charge q by the other ...
*September 6, 2013*

**Physics**

A circular surface with a radius of 0.058 m is exposed to a uniform external electric field of magnitude 1.49 104 N/C. The electric flux through the surface is 74 N · m2/C. What is the angle between the direction of the electric field and the normal to the surface?
*September 6, 2013*

**Physics**

A circular surface with a radius of 0.058 m is exposed to a uniform external electric field of magnitude 1.49 104 N/C. The electric flux through the surface is 74 N · m2/C. What is the angle between the direction of the electric field and the normal to the surface?
*September 6, 2013*

**Physics**

The drawing shows a positive point charge +q1, a second point charge q2 that may be positive or negative, and a spot labeled P, all on the same straight line. The distance d between the two charges is the same as the distance between q1 and the spot P. With q2 present, the ...
*September 6, 2013*

**Science**

Outline a step-by-step method for determining the density of a baseball. Please help with this too! Thanks
*August 31, 2013*

**Science**

Estimate the length of a baseball bat and mass of a baseball in SI units. How can you check how close your estimates are? Please help! Thank you
*August 31, 2013*

**Physics**

When point charges q1=+8.4uC and q2=+5.6uC are brought near each other, each experiences a repulsive force of magnitude 0.66N. Determine the distance between the charges.
*August 28, 2013*

**Physics**

When point charges q1=+8.4uC and q2=+5.6uC are brought near each other, each experiences a repulsive force of magnitude 0.66N. Determine the distance between the charges.
*August 28, 2013*