# Posts by tom

Total # Posts: 1,497

**chemistry**

A 100.0 gram sample of iron at 80.0 degrees Celsius was placed in 150 grams of water at 20.5 degrees Celsius. What was the final temperature when thermal equilibrium was reached?

**chemistry**

At 22 degrees Celsius and a pressure of 755 mm Hg, an unknown gas was found to have a density of 4.52 g/L. When analyzed, the gas was found to consist of two elements: Boron at 78.1% and Hydrogen at 21.9%. What is the molecular formula of this unknown gas?

**Physics**

Wrote the name and subject bad in the other post, sry:: Hello, this is the last question that I can't seem to be able to solve: 1. Jenny (75 kg) goes on a ski trip. She goes down a slope that's inclined at 15*. The drag coefficient of Jenny is 0.300, the surface of ...

**calculus**

Let f(x)=(x^2)+x+14. What is the value of f(x) for which the tangent line to the graph of y=f(x) is parallel to the x-axis?

**Algebra 2**

Dawn is writing a computer program to find the salaries of her employees after their annual raise. The percentage of increase is represented by p in the program. Marty's salary is $23,450 now. Write a polynomial to represent Marty's salary in one year and one to ...

**physics**

A particle is displaced from the point ( 4 m, 12 m ) to the point ( 9 m, 1 m ) in 30 seconds. Calculate the direction (with respect to the positive x axis) of its average velocity vector.

**math**

29x47

**math**

For tax purposes, business frequently depreciate equipment.

**Physics2**

ok thank you drwls!

**Physics**

2 blocks are in contact on a horizontal table. A force is applied on the first block at a 30* angle. The blocks move to the right side. If m1 = 2kg and m2 = 1kg and F = 6 N kinetic friction at the middle of the 2 blocks and the table = 0.250 Find the "contact force" ...

**MATH**

the figure shows that the angle of elevation to the top of the building changes from 20 degree to 40 degree as an observer advances 75 feet toward the building. Find the height of the building to the nearest feet.

**math**

List at least one way in which a scalene triangle and equilateral triangle are the same.

**math**

List at least one way in which an acute triangle and an obtuse triangle are different.

**Physics**

v = fλ 23 m/s = 82Hz * λ λ = 23/82 λ = 0.28048780498 meters apart This one is correct

**Physics**

v = fλ 23 m/s = 84Hz * λ λ = 23/82 λ = 0.28048780498 meters apart

**Physics**

v = fλ 23 m/s = 84Hz * λ λ = 23/84 λ = 0.2738095238 meters apart

**Physics**

A car driving along a highway at a speed of 23 m/s strays onto the shoulder. Evenly spaced parallel grooves called “rumble strips” are carved into the pavement of the shoulder. Rolling over the rumble strips causes the car's wheels to oscillate up and down at a ...

**Chemistry**

a real gas would behave most like an ideal gas under conditions of

**pre algebra**

my numerator is a prime number My denominator is divisible by 2 i am equivalent to 1/5

**Chemistry**

What is the trend in atomic size in the series of Group IIA elements Be through Ra?

**Physics**

A record has an angular speed of 47 rev/min. Through what angle does it rotate in 1.07 s? Answer in units of ra

**Excel-Exponential Fits**

Hey Im trying to plot this set of data: 0 0 10 0.6 20 1.01 30 1.428 40 2 50 2.3 60 2.57 70 2.8 80 3.05 90 3.35 100 3.54 110 3.73 120 3.9 130 4.08 140 4.25 150 4.39 160 4.53 170 4.65 180 4.754 190 4.846 200 4.943 210 5.011 220 5.111 230 5.175 240 5.23 250 5.295 260 5.356 270 5....

**Calculus (2)**

oh I get it now, tnx!

**Calculus (2)**

and how do you get (x+1)?

**Calculus (2)**

Tnx for the quick answer, but I still have a question: why is it - in y' = e^-x (-) (x+2)e^-x instead of a + ?

**Calculus (2)**

find the first and second derivative of: f(x) = (x+2)/e^x I get to: f'(x) = e^x - (x+2)(e^x) / (e^x)^2 I'm stuck at that

**calculus**

last one is supposed to be dy/dx = 1 / ((e^y^2 * 3y^2) - (9^xsin(3y)ln3) - (1+3y))

**calculus**

considering that x is the independent variable in this equation: y + y^3 + 3 = e^y^2 + 3^x * cos(3y) - x Evaluate dy/dx I get to: dy/dx (1+3y) = e^y^2 * 3y^2 * dy/dx + 3^x * ln3 * (-sin(3y)) * 3 *dy/dx -1 Will it give me? dy/dx(1+3y) = dy/dx((e^y^2 * 3y^2) + (3^x * ln3 * (-sin...

**Organic Chemistry**

What is the mechanism for the removal of bromine from dibromocholesterol using Zinc and acetic acid?

**Math**

In Mrs Halls class of 30 students, 17 have computers at home and 20 have cassettes. If 4 students in the class have neither a computer or a cassette, how many of the 30 students have both?

**Maths**

Calculate speed give your answers in km/p hour Distance = 18 KM Time = 12 minutes S - T

**Physics**

In Fig. 6-34, blocks A and B have weights of 46 N and 23 N, respectively. (a) Determine the minimum weight of block C to keep A from sliding if μs between A and the table is 0.21. (b) Block C suddenly is lifted off A. What is the acceleration of block A if μk between...

**Physics**

A student, crazed by final exams, uses a force of magnitude 86 N and angle θ = 61° to push a 5.2 kg block across the ceiling of his room, as in Figure 6-52. If the coefficient of kinetic friction between the block and the ceiling is 0.34, what is the magnitude of the ...

**Physics**

A warehouse worker exerts a constant horizontal force of magnitude 89.0 N on a 43.0 kg box that is initially at rest on the horizontal floor of the warehouse. When the box has moved a distance of 1.60 m, its speed is 1.10 m/s. What is the coefficient of kinetic friction ...

**Physics**

A warehouse worker exerts a constant horizontal force of magnitude 89.0 N on a 43.0 kg box that is initially at rest on the horizontal floor of the warehouse. When the box has moved a distance of 1.60 m, its speed is 1.10 m/s. What is the coefficient of kinetic friction ...

**Physics**

A 3.4 kg block is pushed along a horizontal floor by a force of magnitude 21 N at a downward angle θ = 40°. The coefficient of kinetic friction between the block and the floor is 0.26. What the magnitude of the block's acceleration?

**college physics**

A 0.384 kg puck, initially at rest on a horizon- tal, frictionless surface, is struck by a 0.189 kg puck moving initially along the x axis with a speed of 2.7 m/s. After the collision, the 0.189 kg puck has a speed of 1.7 m/s at an angle of 28 to the positive x axis. ...

**physics**

A 2200 kg car is travelling at 45 km per hour when its brakes are applied and it skids to a stop. If the coefficient of friction between the road and the tires is 0.70 how far does the car go before stopping?

**PHYSICS HELP PLEASE!**

Here is how it is phased in the question: (2) The orbiting space shuttle moves around the Earth well above 99% of the atmosphere, yet it still accumulates an electric charge on its skin due (in part) to the loss of electrons caused by the photoelectric effect from sunlight. ...

**PHYSICS HELP PLEASE!**

The maximum wavelength of light emitted from a blackbody that will emit electrons from a given piece of metal is 255nm. What is the fraction of total energy emitted from the black body that emits electrons? I set up the integral: Int(8πhcλ^-5)/(e^(hc/λkT)-1)) ...

**physics**

A piece of copper is made into a rod with a square cross-section. The side of the square is 2.00 centimeters. The resistivity of copper is 1.7 \cdot 10^{-8} \Omega\cdot {\rm m}. An unknown electric field E, directed along the rod, creates a current of 12.0 amperes through the ...

**PHYSICS**

In a particular region of Earth's atmosphere, the electric field above Earth's surface has been measured to be 151 N/C downward at an altitude of 280 m and 167 N/C downward at an altitude of 430 m. Calculate the volume charge density of the atmosphere, assuming it to ...

**Physics**

An infinitely long line charge of uniform linear charge density λ = -3.00 µC/m lies parallel to the y axis at x = -2.00 m. A point charge of 4.70 µC is located at x = 1.50 m, y = 2.50 m. Find the electric field at x = 2.50 m, y = 2.00 m. I added the vectors, ...

**Physics**

In a particular region of Earth's atmosphere, the electric field above Earth's surface has been measured to be 151 N/C downward at an altitude of 280 m and 167 N/C downward at an altitude of 430 m. Calculate the volume charge density of the atmosphere, assuming it to ...

**algebra**

9/10Y = 36 What is Y

**s.s**

how does gps works

**math**

This is a quadratic equation where perimeter is only 3 sides so p=l x 2w and if width is x then side is 2000-2x then area = x(2000-2x) = 2000x-2x^2 the vertex of this parabola will be x=500 and length is 1000 for area=500000 calculus derivative =2000-4x=0 for max-min point and...

**Chemistry**

The solubility of a certain compound in ice-cold water is 0.22g in 100mL. Its solubility in hot water is 4.35g in 100mL What is the best possible percent recovery we can expect for the re-crystallization of this compound in water?

**chem**

why are electron groups that repel each other higher in energy?

**physics**

yes

**Statistics**

Find the numerical value of k: -2.35=[(k-100)/15]

**statistics**

Based on data collected by the National Center for Health Statistics and made available to the public in the Sample Adult database, an estimate of the percentage of adults who have at some point in their life been told they have hypertension is 23.53 percent. If we select a ...

**math**

decimal value for 1/11

**Math**

angel m1 =125 dagrees angek m2= ?

**chemistry**

If the density of a certain alcohol is 0.785 g/mL, what volume of the alcohol would have a mass of 75.0g?

**spelling**

how do you make a spelling triangle

**finance**

$63,584.00is the correct answer. $80 x 5.68 = 454.40 454.40 x 360 = 163,584.00 163,584.00 - 100,000 = $63,584.00 D.) $63,584.00

**physics**

A car travels along a straight stretch of road. It proceeds for 15 mi at 55 mi/h, then 29 mi at 43 mi/h, and ﬁnally 37.9 mi at 33.7 mi/h. What is the car’s average velocity during the entire trip? Answer in units of mi/h

**chemistry**

Calculate the percent yield if 104 g of CH3CO2CH2CH3 is produced by the reaction of 111 g of CH3CO2H according to the following equation: CH3CO2H(l) + CH3CH2OH(l) ¨ CH3CO2CH2CH3(l) + H2O(l)

**Statistics**

I have recently administered an employee survey at a call center. I found a Pearson r of -.66 between the employees' ages and their scores on an employee engagement scale. What does this finding represent/mean? Also, there is a relationship between gender and employee ...

**chemistry**

Given that ΔHof of copper (II) chloride, CuCl2(s), is –220.1/kJ and ΔHof of copper (I) chloride, CuCl(s), is –137.2 kJ, calculate ΔHo for the reaction when 14.0 g of copper is used: CuCl2(s) + Cu(s) → 2 CuCl(s)

**statistics**

Consider the average available for all hotel rooms from the previous assignment. Identify the point estimate of the average number of available hotel rooms in this lesson from each sample. Construct and Interpret a 95% confidence level for the true mean number of available ...

**Chemistry**

I don't agree this answer. number %khp so high

**physics**

a student tries to open a door at a distance of 1 cm from the hinge at a distance of 10 cm from the hinge and at a distance of 50 cm from the hinge why is a larger force required at 1 cm than at 50 cm?

**telemarketing**

A telemarketer with B2B Communications has a 20 percent historical probability of making a sale during a shift where 100 calls were made. Assign a random variable x, where the value of x is equal to the number of sales made during the shift. Describe the probability ...

**statistic**

The average score on a standardized test is 750 points with a standard deviation of 50 points. If 2,000 students take the test at a local school, how many students do you expect to score between 700 and 800 points?

**statistics**

The average score on a standardized test is 500 points with a standard deviation of 50 points. What is the probability that a student scores between 450 and 600 on the standardized test?

**accounting**

A company has an overhead application rate of 125% of direct labor costs. How much overhead would be allocated to a job if it required total direct labor cost of $20,000? $5,000. $16,000. $25,000. $125,000. $250,000. The R&R Company's production costs for August are: ...

**geometry**

The diagonals of rhombus FGHJ intersect at point K. If side GH is equal to 3x - 10 and side JH is equal to 6x - 19, find x.

**English**

Does anyone know what this verse means: "shall summon to unwelcome bed"? Here is the full stanza of the poem. It is from through the looking glass? Come, hearken then, ere voice of dread, With bitter tidings laden, Shall summon to unwelcome bed A melancholy maiden! ...

**Algebra**

It is possible for a quadratic equation to have no real-number solutions:Solve : x2 + 5x + 3 = 0

**chem**

it dissolves

**algebra 2**

If Q varies inversely as the square root of R and Q=2 when R=4, what is Q when R is 25? does Q=625 im not sure can someone double check it for me.

**algrebra 2**

can someone please help me im stumped on these two. use analytical methods to solve the equation. 1+(1/x)=(42/x²) (7/x-4)=1+(9/x+4)

**algebra**

Solve using the substitution method. Show your work. If the system has no solution or an infinite number of solutions, state this. 4x + 4y = -36 4x + 4y = 12

**Chemistry**

For the reaction HNO3+HCl=NO2Cl+H20 What is the equilibrium constant at 25 C and 75 C

**statistics**

.099

**trig**

sinx+sinxcot^2x=cscx prove each identity

**trig**

tan(theta)-1= sin^2(theta)-cos^2(theta)/ sin(theta)cos(theta)+cos^2(theta) prove each identity

**Chemistry**

sulfur

**chemistry**

what is the volume of 4.4 moles of Cl2 at 285 kelvin and 0.87 atm. (R=0.0821 k*atm/mol*k)

**Math**

3(x-2)+4(2x-6)=6(x-4)+8(2x+1)x=

**Math**

What is the square root of 6 times the square root of 9 if there is no perfect square of 6

**english**

1890-1950 American MLA Format

**english**

I need to write a mini research paper on a modernist poet of my choice... I'm having trouble deciding on what poet to use and how i can develop a strong thesis.. any help would be much appreciated.

**american government**

The factor that normally has the most impact on the president's level of popular support is a. world conditions. b. the condition of the nation's economy. c. the national crime rate.d. the president's skill in the use of television. e. the condition of nation's...

**Statistics**

Suppose that the average grade for all people who take this course in statistics is 83 with a standard deviation of 3.5. If your particular class has an average of 89, can you conclude that your class is better than average at the 90 percent confidence level? Label and ...

**physics**

The function y(x, t) = (25.0 cm) cos(ðx - 15ðt), with x in meters and t in seconds, describes a wave on a taut string. What is the transverse speed for a point on the string at an instant when that point has the displacement y = +22.0 cm?

**Chemistry**

so if the pka is 4.5 the range will be from 3.5 to 5.5?

**Chemistry**

what is the pH range of the buffering region? is that when ph=pKa?

**government**

the federalist papers were written to what? win support for the constitution in new york expose the lack of civil liberties protected in the constitution urge ratification of the constitution in virginia condemn the constitution for the absence of any metioned god

**UCI Chemistry Webworks**

For the following balanced equation: 2 Ag+ (aq) + Cu(s) <<->> Cu2+ (aq) + 2 Ag(s) Which letter corresponds to the correct cell notation at standard state conditions? A. 2Ag+(aq) | Cu2+(aq) || 2Ag(s) | Cu(s) B. Cu(s)| Cu2+(aq) || Ag+(aq) | Ag(s) C. Ag+(aq) | Cu2+(aq...

**account/check please**

answer is A

**math**

do you know how to solve it

**math**

Male: 60,63,65,70,66,80,85,73,79,80,83,85,81,76, 77,90,91,88,78,92 Females: 62,69,70,72,78,77,79,83,80,88,90,90,98,100, 66,67,65,63,69, 83 Can you hellp me I need to find: A) P value and the Z value of this data with a Alpha Value of 0.05.

**MATH Please help me**

Male: 60,63,65,70,66,80,85,73,79,80,83,85,81,76, 77,90,91,88,78,92 Females: 62,69,70,72,78,77,79,83,80,88,90,90,98,100, 66,67,65,63,69, 83 Can you hellp me I need to find: A) P value and the Z value of this data with a Alpha Value of 0.05.

**Math (stastiscs)**

Male: 60,63,65,70,66,80,85,73,79,80,83,85,81,76, 77,90,91,88,78,92 Females: 62,69,70,72,78,77,79,83,80,88,90,90,98,100, 66,67,65,63,69, 83 Can you hellp me I need to find: A) P value and the Z value of this data with a Alpha Value of 0.05.

**Math**

A lawn service will fertilize a lawn at at a rate of 59cents per 100 square feet. What is the price they will charge to fertilize a 125foot x 140foot rectangular lawn? Express answer to the nearest cent.

**math**

1/9