# Posts by dani

Total # Posts: 365

**Chemistry**

a helium balloon is partially filled with 28.7 L of gas at 25.0 degress celcius and a pressure of 1 atm. if the balloon is released and it floats up intp the atmosphere to a heightwhere the pressure is 2.8 x 10^-3 atm and the temperature is -24.0 degrees celcius, calculate the...

*December 8, 2011*

**Algebra II**

alebra is dum

*November 22, 2011*

**math**

its 20 by 30

*November 16, 2011*

**math**

80 goldfish and it doesn't say how deep the aquarium it just says its a 20X30 square inch rectangular aquarium

*November 16, 2011*

**math**

what is the population density if your goldfish population was found in 20x30 sq inch rectangular aquarium?

*November 16, 2011*

**chemistry**

Predict whether nitrate salt solutions containing metal ions with the following outer shell electron configurations will be colored or colorless: [Ar] 3d^2 and [Kr] 4d^10

*November 7, 2011*

**trig**

write a product of two trig functions that equals 1.

*November 6, 2011*

**Chemistry**

Potassium, K, is more reactive than sodium, Na. Calcium, Ca, is less reactive than sodium. The comparative reactivity of these metals is often noted as: K > Na > Ca. Explain the reactivity differences of K, Na, Ca.

*October 31, 2011*

**statistics**

The profit for a new product is given by Z = 2X - 2Y - 7. We know that X and Y are independent random variables with Var(X) = 2 and Var(Y) = 2.7. What is the variance of Z?

*October 24, 2011*

**math**

Is 1 greater than or less than negative 1?

*October 23, 2011*

**chemistry**

the activity series of metals is: Au < Ag < Cu < Sn < Cd < Zn < Al < Mg < Na < Cs which reaction below occutrs spontaneously upong mixing the reageant shown? a) Sn(s) + Al3+ (aq)-> sn2+(aq) + al(s) b) sn(s) + zn 2+ (aq) -> sn 2+ (aq) +zn (s) c...

*October 23, 2011*

**Chemistry**

Thank you!

*October 20, 2011*

**Chemistry**

You observe that when copper is added to a soltion containing gold ions, the copper dissolves and the gold precipitates. Similarly, almost every other metal will displace gold from solutions of gold salts. a) Do these observations mean that gold ion is a unusally good ...

*October 20, 2011*

**Science**

Unrelated species may come to resemble one another over many generations due to

*October 6, 2011*

**algebra**

what is (5x^2-4)+(-3x^2-9)? thanks

*October 4, 2011*

**Physics**

An arrow is shot at a 30 degree angle with the horizontal. It has a velocity of 49m/s. The acceleration of gravity is 9.8 m/s2. How high will the arrow go?

*September 22, 2011*

**Physics**

An arrow is shot at a 30 degree angle with the horizontal. It has a velocity of 49m/s. The acceleration of gravity is 9.8 m/s2. How high will the arrow go?

*September 22, 2011*

**Physics**

An arrow is shot at a 30 degree angle with the horizontal. It has a velocity of 49m/s. The acceleration of gravity is 9.8 m/s2. How high will the arrow go?

*September 22, 2011*

**scientist**

Scientists performed an experiment to determine whether there is a connection between learning ability and food. They took two groups of 20 mice each, all from the same purebred strain. The mice were deprived of food for 3 days and then given a standard learning session in ...

*September 4, 2011*

**Math**

3(7-4)^2??

*August 24, 2011*

**Physics**

Two forces are applied to a car in an effort to move it, as shown in the following figure, where F1 = 402 N and F2 = 364 N. (Assume up and to the right as positive directions.)(F1 is 10degrees and F2 is 30degrees) (a) What is the resultant of these two forces? magnitude ...

*May 3, 2011*

**Physics**

Two objects with masses of 1.00 kg and 7.00 kg are connected by a light string that passes over a frictionless pulley as in the figure below. (a) Determine the tension in the string. (b) Determine the acceleration of each object. (c) Determine the distance each object will ...

*May 3, 2011*

**Physics**

An outfielder throws a 0.150 kg baseball at a speed of 26.0 m/s and an initial angle of 30.0°. What is the kinetic energy of the ball at the highest point of its motion?

*May 3, 2011*

**Physics**

A 7.80-g bullet moving at 530 m/s penetrates a tree trunk to a depth of 6.2 cm. (a) Use work and energy considerations to find the average frictional force that stops the bullet. (b) Assuming the friction force is constant, determine how much time elapses between the moment ...

*May 3, 2011*

**Physics**

A ski jumper starts from rest 51.0 m above the ground on a frictionless track and flies off the track at an angle of 45.0° above the horizontal and at a height of 12.0 m above the ground. Neglect air resistance. (a) What is her speed when she leaves the track? (b) What is ...

*May 3, 2011*

**Physics**

A rifle with a weight of 30 N fires a 3.0 g bullet with a speed of 250 m/s. (a) Find the recoil speed of the rifle. (b) If a 675 N man holds the rifle firmly against his shoulder, find the recoil speed of the man and rifle. I got .245 m/s for the first one but I keep getting ...

*May 3, 2011*

**Physics**

A cannon is mounted on a railway flatcar, the muzzle elevated to 31.4° and pointed in the direction of the track. The cannon fires a 1.10-metric-ton projectile at 1.10 km/s. (a) If the flatcar and cannon together have a mass of 36.0 metric tons (not including the ...

*May 3, 2011*

**Physics**

An electric motor rotating a workshop grinding wheel at a rate of 95 rev/min is switched off. Assume the wheel has a constant negative angular acceleration of magnitude 2.40 rad/s2. (a) How long does it take for the grinding wheel to stop? (b) Through how many radians has the ...

*May 3, 2011*

**Physics**

A 55.0 kg ice skater is moving at 4.04 m/s when she grabs the loose end of a rope, the opposite end of which is tied to a pole. She then moves in a circle of radius 0.795 m around the pole. (a) Determine the force exerted by the horizontal rope on her arms. (b) Compare this ...

*May 3, 2011*

**Physics**

objects with masses of 285 kg and a 585 kg are separated by 0.420 m. (a) Find the net gravitational force exerted by these objects on a 62.0 kg object placed midway between them.

*May 3, 2011*

**physics**

A solid, horizontal cylinder of mass 8.0 kg and radius 1.30 m rotates with an angular speed of 5.50 rad/s about a fixed vertical axis through its center. A 0.250 kg piece of putty is dropped vertically onto the cylinder at a point 0.900 m from the center of rotation, and ...

*May 3, 2011*

**Math**

Lawrence records the number of minutes he reads each day show below Day 1: 75 mins Day 2: 30 mins Day 3: 25 mins Day 4: 50 mins Day 5: 80 mins How many minutes must Lawrence read on the sixth dat of have mean of 55 minutes read for the 6 day?

*April 18, 2011*

**Math**

Triangle ABC is an obtuse triangle with two congruent angles. If m< C = 108 write an expression that represents m<A

*April 17, 2011*

**smk n2**

Tent. sudut yang lebih kecil dari perpotongan bidang 5x-14y+2z-8=0 dan 10x-11y+2z+5=0 (tent sudut antara normal-normalnya)

*April 14, 2011*

**Math**

What is probability

*March 30, 2011*

**Calc**

The temperature at any point in the plane is given by function f(x,y) = 100/(x^(2)+y^(2)+1). Find a direction at the point (3,2) in which the temperature does not increase or decrease. Help, please? Thank you.

*February 27, 2011*

**Calc**

The directional derivative of z = f(x,y) at (2,1) in the direction toward the point (1,3) is -2/sqrt(5), and the directional derivative in the direction toward the point (5,5) is 1. Compute dz/dx and dz/dy at (2,1). I have no idea how to solve this problem. Help, please? Thank...

*February 27, 2011*

**MATH**

A rectangular flower is 20 inches long,8 inches wide ,and 6 inches high . True of false. If andy fills the flower pot 2/3 full of soil, the expression 2/3(20 + 8 + 6) could be used to find the about of soil he needed.

*February 27, 2011*

**ALGEBRA**

i need help with this problem

*February 23, 2011*

**Chemistry Help!!**

a kilogram of aluminum metal and a kilogram of water are each warmed to 75 degree Celsius and placed in two identical insulated containers. one hour later, the two containers are opened and the temperature of each substance is measured. the aluminum has cooled to 35 degree ...

*January 19, 2011*

**Physics**

A 14,245N auto with a velocity of 6.0m/s crashes into a brick wall. If the car moves 64.0 cm before coming to a stop, what average force does the car exert on the wall?

*January 13, 2011*

**Physics**

A 14,245N auto with a velocity of 6.0m/s crashes into a brick wall. If the car moves 64.0 cm before coming to a stop, what average force does the car exert on the wall?

*January 13, 2011*

**math**

80.00

*December 26, 2010*

**chem: gases, liquids, solids**

How many kilojoules of heat is required to completely covert 60.0 grams of water at 32.0° C to steam at 100°C? For water: s = 4.179 J/g °C (delta)H fusion = 6.01 kJ/mol (delta)H vap = 40.7 kJ/mol

*November 30, 2010*

**Chemistry: gases, liquids, solids problem**

4 NH4NO3 -> 8 H2O + 4 N2 + 2 O2 What will be the total volume in liters of gas produced at 720. mm Hg and 570.0°C when 2.50 g of NH4NO3 completely decomposes? Use molar masses with at least as many significant figures as the data given.

*November 30, 2010*

**Chemistry**

thanks Liliana! and everyone else.

*November 20, 2010*

**science**

explain why a single5 500 kg block of granite weathers much more slowly than 100 chunks of granite weighing 5 kg each.

*November 18, 2010*

**chemistry**

A 3.0% by mass solution of H2O2 contains 3.0 g of H2O2 per 100 g of solution. (3.0 g H2O2 / 100 g solution) x (1.01 g solution / 1 mL solution) x (1000 mL / L) = 30.3 g H2O2 / L (30.3 g H2O2 / L) x (1 mole H2O2 / 34.01 g H2O2) = 0.8909 moles H2O2 / L = 0.89 M to 2 sig figs

*November 17, 2010*

**math**

_______7m______ |\ / | | \ 2.8m 2.8m / | | \ / | | n \ / | | / \ n | | / \ | | / \ | / 2.8m 2.8m \ | ____________ \ | Find the area of each shaded region( n not shaded). Assume that all angles that appear to be right angles are right angles.

*November 16, 2010*

**Math**

This irregular shape has 2m,2m,2m, 3m, 4m, 7m _2m_ _2m_ | |2m__3m_| | | | |________| 4 m 7 m how would I find the area if you can't tell how it is so you can't answer it I understand

*November 16, 2010*

**Math**

A= 10,560 ft x 2 mi

*November 16, 2010*

**Math**

Find the measures of two supplementary angles if the difference of their measures is 56 degrees I know supplementary angles are the sum of the measure if two angles is 180 degrees but then what is the question asking?

*November 16, 2010*

**math**

A= 5 m x 200 cm A= 500 cm x 200 cm A= 100000 cm2?

*November 16, 2010*

**math**

How do areas of two parallelgrams compare when the dimensions of one are three times the demensions of the other?

*November 16, 2010*

**math**

A= 100 cm x 1 m A= 100 cm x 100 cm A=10000 cm2?

*November 16, 2010*

**math 7th**

similar figuers have the same shap but not the nesessarily the same size. They have corresponding angles and corresponding sides. What exactly do you need help with?

*November 16, 2010*

**math**

but I don't get how to tell if it is m or cm

*November 16, 2010*

**math**

A= 0.5 m x 20 cm

*November 16, 2010*

**math**

the answer is 1m2

*November 16, 2010*

**math**

A square with an top as 100cm and a side with 1 m A= b x h A= 100 x1 A= 100 cm2 or m2?

*November 16, 2010*

**Weather & Climate (science)**

Why is it that an Aneriod Barometer Can be used to measure elevation as well as air pressure?

*September 14, 2010*

**math**

How are sales tax and discounts figured? specifically socks @ $2.99 and 5.5% sales tax

*September 12, 2010*

**biology**

when the peple are having s*x

*September 8, 2010*

**Weather & Climate (science)**

okayy and there are alot more questionss

*September 8, 2010*

**Weather & Climate (science)**

Which ones/one is true? a.)Altitude affects density b.)Altituce is the dictance above sea level c.)Altitude is also call elevation

*September 8, 2010*

**Weather & Climate (science)**

Thankss

*September 8, 2010*

**Weather & Climate (science)**

1.A(an)_________________ barometer Has a closed space surrounded by metal 2.A(an)_________________ barometer Has a glass tube that is open at the bottom end. ive been tryin thesse for ever! when awncering put like for example ur goi no awncer #1 put 1. then the awncerr

*September 8, 2010*

**science**

either e or c

*September 8, 2010*

**Weather & Climate (science)**

i just added them to the current questions

*September 8, 2010*

**Weather & Climate (science)**

Thankss. Can you help me with some more problemss?

*September 8, 2010*

**Weather & Climate (science)**

1. an insturment used to measure air pressure is a(an)___________________________________.

*September 8, 2010*

**Algebra/Word problem**

320! i thinkk

*September 8, 2010*

**7th grade**

what he said

*September 8, 2010*

**spanish**

Correctt

*September 8, 2010*

**Physics**

A,h=23m B.56m

*September 4, 2010*

**6th grade math**

But how does it answer in part related to factors of 10

*August 31, 2010*

**math**

i need some serious help with limits in pre-calc. here are a few questions that i really do not understand. 1. Evaluate: lim (3x^3-2x^2+5) x--> -1 2. Evaluate: lim [ln(4x+1) x-->2 3. Evaluate: lim[cos(pi x/3)] x-->2 4. Evaluate: lim x^2+x-6/x^2-9 x--> -3 5. ...

*July 13, 2010*

**statistics**

Give an estimate for each expression in Exercises, Then state whether you believe that the exact answer is greater than or less than the estimate. Explain how you decided. Use a calculator to check the accuracy of your estimate. 978 X 66

*July 10, 2010*

**computers**

Can you find both multitasking system and a multiprocessing system operating system?

*May 26, 2010*

**algebra**

Thank you for the information.

*May 13, 2010*

**algebra**

I have one more step in my question. I have to Find the value of 10^-2.4 by putting this value in a calculator. I do not have a calculator to do this, can anyone help me out?

*May 13, 2010*

**language**

Because a compound is when two words are joined together to make one word. Black alone ia a word. Is ness?

*May 9, 2010*

**language**

no examples eye + ball= eyeball grand + mother = grandmother

*May 9, 2010*

**language**

A compound word is made when two words are joined to form a new word

*May 9, 2010*

**language**

Homonyms are words that sound like one another but have different meanings. B

*May 9, 2010*

**Algebra- IS this right?**

Evaluate The Logarithmic Equation For 3 Values Of X Greater Than -1 3 Between -2&-1 &x=-1 Y = Ln(x + 2) Y = Ln(x + 2) ,x=3,y=1.6,1.6>-1. X=-1,y=0.

*May 9, 2010*

**Algebra- IS this right**

Evaluate The Exponential Equation For 3 Positive, 3 Neg. Values Of X &x=0 Y=3^-x" Y=3^-x,x=3y=1/27, x=-3,y=27,x=0,y=1.

*May 9, 2010*

**Algebra**

I need to rewrite the following as an equivalent logarithmic yt = x I wrote logy=logt=logx. My teacher said that was wrong. Can someone guide me on the right answer?

*May 8, 2010*

**Algebra**

Given log b 3 = 0.8397 and log b 7 = 1.4873. Find log b 3b Is the right answer 0.8397

*May 7, 2010*

**algebra**

My choices for this question are a x = log8 over log 3 b x log = log 8 c x=log 3 over log 8 d x= ln8 over ln3

*May 5, 2010*

**algebra**

My choices for this question are a x = log8 over log 3 b x log = log 8 c x=log 3 over log 8 d x= ln8 over ln3

*May 5, 2010*

**algebra**

Can you please tell me me if the expression or equation that is equivant to 8^x=3 would be x log 3 = log 8?

*May 5, 2010*

**algebra**

Rewrite the following as an equivalent logarithmic equation.Do not solve. y^t = x answer logy+logt=logx-is this right also Express as an equivalent expression that is a sum of logt (3ab) the t is at the bottom of the g answer log3+loga+logb logarithms.

*May 5, 2010*

**Is this right**

I need to express as an equivalent expression that is a sum of logarithms. logt 13ab2 is this right (log+13t+loga+log+b+log+2)

*May 4, 2010*

**Is this algebra question right**

Do you rewrite the following as an equivalent logarithmic equation yt=x as E^2-2=7.3891?

*May 4, 2010*

**Algebra**

what would be the approximation to the nearest ten-thousandth log 8900 over log 110?

*May 4, 2010*

**algebra**

Not sure where to go next. I need to solve this quadratic equation 7x^2-5=0. This is what I have so far, not sure where/what to do next x=2/7 x=sqrt2/7 or x=-sqrt2/7* =+/-sqrt2/7 +/-sqrt14/7 not even sure if this is right.

*May 3, 2010*

**algebra-Am I right so far**

Use the quadratic formula to determine the x-intercepts (if any)f(x)=2x^2=2 am I right so far? f(x)ax^2+bx+c y=ax^2+bx+c y=2x^2+2 y=0=>2x^2+2=0 =>2x^2+2=0 ax^2=2,bx=2,c=0 x=b=sqrtb^2+4ac over 2a x=(2)+sqrt(2)^24(2)(0)over2(2) x=sqrt4+4over 2

*May 2, 2010*

**algebra**

Is the line of symmetry in f(x)= -(x-2)^2+2 x=2

*April 28, 2010*