Friday
April 29, 2016

Posts by becky

Total # Posts: 564

math
the half life of the carbon isotope C14 is about 5700 years. A. about how many years does it take 1000 grams of this substance to decay to 500 grams? B. about what percent of the original amount would you expect to find after 1000 years?
October 9, 2013

physics
A 74 kg box rests on a level surface. The coefficient of static friction, µS = 1.1 and the coefficient of kinetic friction, µK = 0.7 . What is the magnitude of Friction on the box from the surface?
October 4, 2013

grammar
In Which oneof the following sentences is the number written correctly? A.the parcel of land was advertised as two hundred forty-three and three-quarters acres.b.the college has an,endowment of more than $187million.c.john just paid $33 thousand forhis New car.d.one hundred ...
August 8, 2013

Algebra
A $130,000 home bought with a 20% down payment and the balance financed for 30 years at 7.5% Find the monthly payment for the loan
June 5, 2013

CENCEPTS IN HEALTHCARE
what is the procedures and resources available for assisting patients who use English as a second language, who is hearing impaired, sight impaired, or who have any other type of physical or diversity related disposition that should be addressed to provide quality care to that...
June 2, 2013

chemistry
i have never used the ice table before so i think its basic class. so do i just add those 2 numbers together? Thanks DrBob
May 19, 2013

chemistry
What is the hydrogen ion concentration, in mol dm−3, when 2.00 g of sulfuric acid is dissolved in water to give 0.400 dm3 of solution? could you explain in a simple and clear way please because im not very good at chemistry. thanks in advance
May 19, 2013

PreCalculus
Sin5x cos2x + cos5x sin2x=
May 13, 2013

geometry
were did you show me I dont have anything
May 4, 2013

geometry
How much more pizza is in a 12-in. diameter pizza than an 8-in. diameter pizza? Round your answer to the nearest hundredth. Be sure to show all work and label your answer. TWO points for the work...TWO points for the corrrect answer
May 4, 2013

geometry
4.2
May 4, 2013

social studies
making laws
April 21, 2013

social studies
The main work of representatives in a parliament is a.running trials b.trining an army c. kkeeping the peace d.making laws
April 21, 2013

Physics (Algebra-based)
A barefoot field-goal kicker imparts a speed of 35 m/s to a football initially at rest. If the football has a mass of 0.39 kg and the time of contact with the ball is 0.038 s, what is the force exerted by the ball on the kicker’s foot? I tried the formula F=(m(vf-vi))/...
April 17, 2013

physics
An elevator has a mass of 500 kg. It may safely carry an additional mass of 1000kg and accelerate upward at 2m/s2. What is the tension in the cable?
April 14, 2013

Physics (Algebra-based)
Thank you!
April 6, 2013

Physics (Algebra-based)
A block starts at rest and slides down a frictionless track except for a small rough area on a horizontal section of the track.It leaves the track horizontally, flies through the air, and subsequently strikes the ground. gravity= 9.81 m/s^2. height1=4.1m---- is initially ...
April 6, 2013

help
If you triple 4 and subtract 2 each day, how many days until you have zero?*
April 4, 2013

math
10
March 14, 2013

math
10 pounds
March 14, 2013

Physics (Algerbra-based)
Thank you!
March 14, 2013

Physics (Algerbra-based)
A particle is moving clockwise around a circle with a radius 3.31 m. The magnitude of the total acceleration of the particle at the given instant is 14.3 m/s^2; the angle between the vector of total acceleration and the radius-vector of the particle is 30◦. Find the ...
March 14, 2013

Math
David has 50 bills in his wallet worth $400 all fives and tens dollar bills. How many of each bill does he have
March 8, 2013

algebra
A line with a slope of -2 passes through the point (1, 7). What is the closest point on the line above (1, 7) which has whole number coordinates?
March 4, 2013

Geography
Would outdoor locations in countries such as Singapore with the highest temperatures also have the highest relative humidities? Explain 2 reasons? Would outdoor locations in countries such as Singapore with the highest temperatures necessarily have the highest dew point ...
March 2, 2013

Math
A bag contains two blue, three purple, four yellow, two red, three green and one orange marbles. What is the conditional probability that, without replacement, the second marble is purple given that the first marble was green?
February 23, 2013

science
describe how matter cycles through an ecosystem
February 13, 2013

Calculus
Find the derivative of m(x)=1/(x+1) by using the definition of the derivative.
February 12, 2013

Calculus
k=+/- 8 I figured it out.
February 4, 2013

Calculus
It is supposed to be x^2-k^2 over x-8 And the limit is 8
February 4, 2013

Calculus
Find a value of the constant k such that the limit exists. x^2-k^2 lim _________ x->8 x-8 k=+/_
February 4, 2013

Pre-Calculus
An Alfa Romeo going at 70 mph requires 169 feet to stop. Assuming that the stopping distance is proportional to the square of velocity, find the stopping distances required by an Alfa Romeo going at 35 mph and at 140 mph (its top speed).
February 3, 2013

Pre-Calculus
A pomegranate is thrown from a ground level straight up into the air at time t = 0 with velocity 67 feet per second. Its height at time t seconds is f(t)=-16^2+67t. (a) Find the time it hits the ground and (b) the time it reaches its highest point. (c) What is the maximum ...
January 31, 2013

Pre-Calculus
For a boat to float in a tidal bay, the water must be at least 2.5 meters deep. The depth of the water around the boat, d(t), in meters, where t is measured in hours since midnight, is d(t)=5+4.6sin(0.5t) Use three decimal places in all intermediate calculations. (a) What is ...
January 28, 2013

Pre-Calculus
Find a solution to the equation if possible. Give the answer in exact form and in decimal form rounded to three decimal places. 1=21tan(2x+2)-6
January 28, 2013

3rd grade math
30/100 = 3/10
January 28, 2013

Pre-Calculus
The exponential function y(x)=Ce^ax satisfies the conditions y(0)=6 and y(1)=7. (a) Find the constants C and a. Enter the exact value of a. (b) Find y(2). Enter the exact answer. Simplify the answer so it does not contain any logarithms.
January 28, 2013

Pre-Calculus
At time t hours after taking the cough suppressant hydrocodone bitartrate, the amount A, in mg, remaining in the body is given by A=13(0.82)^t. a) What was the initial amount taken? b) What percent of the drug leaves the body each hour? c) How much of the drug is left in the ...
January 28, 2013

math
Chord BC is drawn in a circle with a radius of 3cm. Chord BS is 4cm long. Find the perpendicular distance from A to chord BC
January 20, 2013

Early Child Educ.
the newest organization to accredit afterschool programs is the
December 27, 2012

BIOCHEMISTRY. PLEASE HELP! URGENT!!!!!
Appreciate if you could help me answering the following questions! thank you!! How would you prepare a 20% homogenate from a 2.0g of liver using 0.25M sucrose? why is it necessary to cool the homogenate during homogenization?
December 2, 2012

Biochemistry
Appreciate if you could help me answering the following questions! thank you!! How would you prepare a 20% homogenate from a 2.0g of liver using 0.25M sucrose? why is it necessary to cool the homogenate during homogenization?
December 1, 2012

Chemestry
Find the molarity of a solution containing 0.75 mol of NaCl with a volume of 1.5 L.
November 23, 2012

Math
Ella walked 4.5 km/h to her friends house. She walked back home from her friends house at 3.5 km/h. She walked a total of 40 minutes. How many minutes was her walk on her way to her friends house?
November 19, 2012

algebra
my scenario, to start a small business you will need a loan of $50.000 to purchase the restaurant. The bank interest rate 9% that compounds monthly for 7 years. What is the monthly payment for this loan, what is the fomula that you will use and the values for each variable to ...
November 12, 2012

algebra
a small business loan in the amount of 50,000 need to interest rate of 9% that compounds monthly for 7 years. What is the payment for 7 years, need formula for this. And what is the balance of the loan at the end of the 1st year? Show the formula used for each variable and the...
November 12, 2012

CALC #
Use Green's Theorem to evaluate F · dr. C (Check the orientation of the curve before applying the theorem.) F(x, y) = y cos x − xy sin x, xy + x cos x , C is the triangle from (0, 0) to (0, 12) to (3, 0) to (0, 0)
November 9, 2012

math
how do you figure out the diameter of a pipe that is 40 feet high and holds 200000 gallons
October 23, 2012

Chemistry
thank you!!
October 21, 2012

Chemistry
someone help pls!! percentage of ethanol in the "blood" sample on a v/v basis is 0.0143% v/v. is the "blood" sample analysed over the limit for driving? (legal limit is 80mg alcohol per 100mL blood. assume the density of ethanol is 0.785g/mL and the density...
October 21, 2012

Algebra
4ã(50x)+3ã(2x)+ã(72x) Combine. Assume that all variables represent nonnegative real numbers.
October 15, 2012

Calc 3
The DNA molecule has the shape of a double helix. The radius of each helix is about 10 angstroms (1 Å = 10−8 cm). Each helix rises about 34 Å during each complete turn, and there are about 2.9 × 108 complete turns. Estimate the length of each helix. (...
October 10, 2012

Calc 3 PLEASE HELP!!!!
no you have to use lagrange multipliers to do it and i figured out all five equations but i can not solve any of them
October 4, 2012

Calc 3 PLEASE HELP!!!!
Find the maximum and minimum volumes of a rectangular box whose surface area is 1300 cm2 and whose total edge length is 200 cm.
October 4, 2012

Calc 3
If a function of one variable is continuous on an interval and has only one critical number, then a local maximum has to be an absolute maximum. But this is not true for functions of two variables. Show that the function f(x,y)= 3xe^y − x^3 − e^(3y )has exactly one...
October 1, 2012

Math
The base of an isosceles triangle is one inch shorter than the equal sides, and the altitude of the triangle is two inches shorter than the equal sides. What is the length of the equal sides?
September 30, 2012

chemistry
Identify a haloalkane and describe the manner in which it functions as an anesthetic.
September 29, 2012

Calc 3
Find parametric equations for the tangent line to the curve of intersection of the paraboloid z = x^2 + y^2 and the ellipsoid 6x^2 + 5y^2 + 7z^2 = 39 at the point (−1, 1, 2)
September 28, 2012

Calc 3
can you please explain to me where you got the numbers for T(-1,1,2) I know you did the cross product but I can not seem to get the same numbers as you. Please explain
September 27, 2012

Calc 3
Find parametric equations for the tangent line to the curve of intersection of the paraboloid z = x2 + y2 and the ellipsoid 6x2 + 5y2 + 7z2 = 39 at the point (−1, 1, 2)
September 27, 2012

Calc 3
At what point on the paraboloid y = x2 + z2 is the tangent plane parallel to the plane 7x + 2y + 3z = 2? (If an answer does not exist, enter DNE.)
September 27, 2012

Lang Arts
Would #2 be A?
September 25, 2012

physics
Two blocks are connected by a lightweight, flexible cord that passes over a frictionless pulley. If m1 = 3.8 kg and m2 = 9.2 kg, and block 2 is initially at rest 140 cm above the floor, how long does it take block 2 to reach the floor?
September 23, 2012

physics
Two blocks are connected by a lightweight, flexible cord that passes over a frictionless pulley. If m1 = 3.8 kg and m2 = 9.2 kg, and block 2 is initially at rest 140 cm above the floor, how long does it take block 2 to reach the floor?
September 23, 2012

Calc 3
thank you!!!!!!
September 22, 2012

Calc 3
Use the Chain Rule to find ∂z/∂s and ∂z/∂t. z = tan(u/v), u = 7s + 4t, v = 4s − 7t
September 22, 2012

Calc 3
we were not given f(x,y) the whole problem is listed above, apparently there is a link that is supposed to help us but I followed it and don't know what I am doing wrong and I cannot post the link because it is on a special homework website.
September 22, 2012

Calc 3
If z = f(x, y), where x = r^2 + s^2 and y = 8rs, find ∂^2z/(∂r ∂s).
September 22, 2012

calc 3
yes i already got parts a and b i do not know how to do part c sorry i should have specified that in my post
September 21, 2012

calc 3
The length script l, width w, and height h of a box change with time. At a certain instant the dimensions are script l = 7 m and w = h = 5 m, and script l and w are increasing at a rate of 6 m/s while h is decreasing at a rate of 4 m/s. At that instant find the rates at which ...
September 21, 2012

English
1.I started play the oboe because [I've heard] it was a challenging instrument (a) no change (b) I'd have heard (c)I've been hearing (d) I'd heard 2. That was [four years ago and, I've] enjoyed learning to play (f) no change (g) four years ago, and I've...
September 20, 2012

physics
A crate of potatoes of mass 13.0 kg is on a ramp with angle of incline 30° to the horizontal. The coefficients of friction are μs = 0.76 and μk = 0.35. Find the frictional force (magnitude and direction) on the crate if the crate is sliding up the ramp.
September 20, 2012

calc 3
Use the Chain Rule to find dw/dt. w = ln (x^2 + y^2 + z^2)^.5 , x = 9 sin t, y = 6 cos t, z = 7 tan t
September 20, 2012

Calc 3
Find all partial derivatives? v = (xy)/(x-y) vxx= vxy= vyx= vyy=
September 20, 2012

physics
A barge is hauled along a straight-line section of canal by two horses harnessed to tow ropes and walking along the tow paths on either side of the canal. Each horse pulls with a force of 540 N at an angle of 12° with the centerline of the canal. What is the net force on ...
September 19, 2012

calc 3
Find all partial derivatives? v = (xy)/(x-y) vxx= vxy= vyx= vyy=
September 19, 2012

calc 3
Use polar coordinates to find the limit. [If (r, θ) are polar coordinates of the point (x, y) with r ≥ 0, note that r → 0+ as (x, y) → (0, 0).] (If an answer does not exist, enter DNE.) lim (x, y)→(0, 0) [(3e^−x^2− y^2) − 3]/ (x^2...
September 17, 2012

Calc 3
but there is no lHospitals rule in multivariable
September 14, 2012

Calc 3
Find the limit, if it exists. (If an answer does not exist, enter DNE.) lim (x, y)→(0, 0) of (x^2 + y^2)/[((x^2 + y^2 +64)^.5)-8]
September 14, 2012

Calc 3
A cooling tower for a nuclear reactor is to be constructed in the shape of a hyperboloid of one sheet. The diameter at the base is 300 m and the minimum diameter, 500 m above the base, is 200 m. Find an equation describing the shape of the tower in the coordinates where the ...
September 12, 2012

Chemistry
1.42 g/cm^2 to mg/mm^2
September 4, 2012

calc 3
The magnitude of a velocity vector is called speed. Suppose that a wind is blowing from the direction N45°W at a speed of 40 km/h. (This means that the direction from which the wind blows is 45° west of the northerly direction.) A pilot is steering a plane in the ...
August 31, 2012

calc 3
Question Find an equation of the set of all points equidistant from the points A(−2, 5, 2) and B(5, 1, −3).
August 30, 2012

calculus
hi i think i know what you mean already. my answer for F"(v) (-150v^5/2 + 40500v)/v^4 i simplified further, it became (-150v(v^3/2 - 270))/v^4 cancel off the common factor v it became (-150(v^3/2 - 270))/v^3 Am i correct??
August 13, 2012

calculus
based on my question, i retyped... F(v) : (600v^3/2 + 20250)/v F'(v) : (300v^3/2 - 20250)/v^2 F"(v) : (-150v^5/2 + 40500)/v^3 Reiny, isn't your answer suppose to be f(x) = 600 v^(3/2) + 20250 v^-1, instead of f(x) = 600 v^(1/2) + 20250 v^-1 ?? 1/2 power and 3/2 ...
August 13, 2012

calculus
I do not want the simplified answer by the way...I need the answer as an expression only
August 13, 2012

calculus
Ok but the power 5/2 is wrong? Should have been power 3/2? I keep on getting the answer 5/2.. I don't know which part of my working is wrong
August 13, 2012

calculus
Just want to check whether my answer is correct for quotient rule F(v) : (600^3/2 + 20250)/v F'(v) : (300^3/2 - 20250)/v^2 F"(v) : (-150v^5/2 + 40500)/v^3 Can anyone let me know whether my answer is correct for first and second derivative based on F(v) ??
August 13, 2012

calculus
yes it should be, F(v) : (600^3/2 + 20250)/v F'(v) : (300^3/2 - 20250)/v^2 F"(v) : (-150v^5/2 + 40500)/v^3 for F"(v), this is how i get: F'(v) : (300^3/2 - 20250)/v^2 F"(v) : ((300v^3/2 - 20250)' * v^2) - ((300v^3/2 - 20250) * (v^2)')/v^4 F"...
August 13, 2012

calculus
nope, it's not a typo. the 5/2 is the power of 5 over 2. it is not 5 divide by 2. is my above answer correct?
August 13, 2012

calculus
Just want to check whether my answer is correct for quotient rule F(x) : (600^3/2 + 20250)/v F'(x) : (300^3/2 - 20250)/v^2 F"(x) : (-150v^5/2 + 40500)/v^3 Can anyone let me know whether my answer is correct for first and second derivative based on F(x) ?? Thank you!!
August 13, 2012

calculus
A ship uses $( 7v^2 ) of fuel per hour when travelling at a constant speed of v km/h. Other expenses in operating the ship (i.e. crew and equipment) amount to $345 per hour. The ship makes a journey of 100 km. C(v) : (700v^2 + 34500)/v C'(v): (700v^2 - 34500)/v^2 C"(v...
August 13, 2012

calculus
i got the answer!! thank you!!!
August 13, 2012

calculus
pls ignore the above question... to make it clearer for the question, it is... f(x): (700v^2 + 34500)/v f'(x) : (700v^2 -34500)/v^2 f''(x) : ???
August 13, 2012

calculus
The question should be: f(x): 700v^2 + 34500/v f'(x) : 700v^2 -34500/v^2 f''(x) : ???
August 13, 2012

calculus
sorry typo error above, question is, f(x): 700v^2 + 34500/v f'(x) : 700v^2 -34500/v^2 f"'(x) : ???
August 13, 2012

calculus
how to find the second derivative of quotient rule? f(x): 700v^2 + 3450/v f'(x) : 700v^2 -3450/v^2 f"'(x) : ???
August 13, 2012

calculus
The 5 question is asking how many km/h...appreciated if anyone cld help...thank you!!
August 12, 2012

calculus
Hi i need help in this. Some of the parts i got the answer but some i don't. please help! A ship uses $(7v^2) of fuel per hour when travelling at a constant speed of v km/h. Other expenses in operating the ship (i.e. crew and equipment) amount to $345 per hour. The ship ...
August 12, 2012

calculus
i get the answer already! thank you!
August 11, 2012

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