Friday
April 18, 2014

Posts by bob


Total # Posts: 2,359

Physics
A ball is rolled off the flat roof of a 15-storey building that is 45 m above a playground. When will the ball strike the ground if you can ignore air resistance? If you believe that there is not enough information given, explain what is needed.

Physics
I would say they hit the ground at the same time but im not sure

Physics
Two identical balls roll off the edge of a horizontal table top. One leaves traveling at twice the speed of the other. Which ball hits the floor first? Why?

Physics
A baseball is hit with a horizontal speed of 22 m/s and a vertical speed of 14 m/s upward. What are these speeds 1 s later?

Physics
I would say the true mass is 60 kg and thats as far as i got

Physics
You stand on a bathroom scale that rests on the floor of an elevator. Standing on the scale compresses internal springs and activates a dial that indicates your weight in newtons. When the elevator is at rest, the scale reads 600 N. Then the elevator begins to move upward with...

math
Express the infinite series below using sigma notation and then find the sum. 64 + 40 + 25 + 15.625... Any explanation would be excellent. Thank you so much.

Physics
Tom Brady (the Patriots’ quarterback) throws a football – at a speed of 30 mph at an angle of 50 degrees to the horizontal – toward an intended receiver 20 yd straight downfield behind the goal-line. The pass is released 7.5 ft above the ground. Assume that the ...

Physics
A juggler has a set of balls that she can toss into the air. If it takes her 0.2 s to transfer a ball from the receiving hand to the launch hand and she is able to throw a given ball straight up with a maximum speed of 10 m/s how many balls can she successfully juggle at any t...

Physics
Thanks a lot Elena

Physics
Two friends are at the local high school track, a circle measuring 440 yards for one complete lap. Abe can jog at 8.2 miles per hour while Bob’s jogging speed is 4.6 miles per hour. If they both start at the same point and jog in the same direction (say clockwise), how ma...

Marketing
What is the preparation of reports for each level of responsibility in the company’s organization chart called?

Marketing
Managerial accounting is

Math
Mr. Rainier's car uses about 1.6 fluid ounces of gas per minute when the engine is idling. One night, he parked his car but forgot to turn off the motor. He had just filled his tank. His tank holds 12 gallons. About how many hours will it take before his car runs out of gas?

chemistry
YES! it was the OH^- that messed up my calculation. The answer you provided me was correct, thanks for all the help!

chemistry
for the %protonation = [(OH^-)/(BN)]*100 i tried doing 1.15*10^-3 / 0.39 * 100 = .295, but the answer is incorrect. can you tell me what i did wrong?

chemistry
nvm, it IS right, ty xD

chemistry
-log ka=8.52 ka= 3*10^-09 Kb= kw/ka = 10^-14/ 3*10^-09 = 3.4 *10^-06 kb= x^2/0.39 x= squre root of ( 3.4*10^-6*0.39) =1.15*10^-3 POH= -log[OH-]= -logx= -log 1.15*10^-3 =2.939 PH= 14 - 2.939 =11.06 IS THIS RIGHT?

chemistry
Calculate the pH and percentage protonation of the solute in an aqueous solution of 0.39 M quinine if the pKa of its conjugate acid is 8.52.

english
Durig literacy analysis, the writer reads a work and then

math
tom had 8 pieces of pizza, tom ate one. How much is left

Grade 11 Math
Thanks that seems to have worked the back of my text book says it is 2.1 but i got 2.5 close enough.

Grade 11 Math
jackie mows a stip of uniform width around her 25m by 15m rectangular lawn and leaves a patch of lawn that is 60% of the original area. What is the width of the strip?

Networking
In your browser, you enter the URL of a website you use daily. After some delay, you receive a DNS error message that the host does not exist. a) What may have happened? Explain your reasoning. b) How would you logically disconfirm or test each possibility?

Networking
Assume that an average SNMP response message is 100 bytes long. Assume that a manager sends 40 SNMP Get commands each second. What percentage of a 128 kbps WAN link would the response message represent?

history
what event caused the greek city- states to put aside their differences.

physics
Two waves traveling on a string in the same direction both have a frequency of 100 Hz, a wavelength of 2cm and an amplitude of .02 m. What is the amplitude of the resultant wave if the original waves differ in phase (a) by Pi/6 and (b) by Pi/3

chem
Hey could you please help me. Why would K2CO3 be a better drying agent than Na2SO4 when drying out water from clohexanol?

Math
what is the median of the numbers 3,6,10,12,27,62

physics energy
A potential function is given by U(x) = 18 x^2. What will be the acceleration (in meters/second ^2) of a 8.00 kg mass, when it is at the position x = 0.500 m?

chemistry
What is the limiting reactant of 4000 grams of heptane is combusted with 7000 grams of oxygen?

Pre-calculus
Use the remainder theorem to find which of the following is not a factor of x3 + 12x2 + 47x + 60 the answer is x-5 but idk why

trig
simplify cox^2x-cos^4x

Chemistry
? lost- what chart?

Chemistry 2
(.032^2)x(.016^-1)^2 =4

Chemistry 2
i still dont get this

Mechanics for A-level
An object of mass 50kg rests on a rough plane inclined at an angle z to the horizontal. It is supported in this position by a light string parallel to the plane which is attached to the object and fixed to a point at the top of the plane. The string has a breaking strain of 20...

finite math
Determine whether each system of linear equations has a)one and only one solution, b)infinitely many solutions, or c) no solution 2x-4y=5 3x +2y=6

physics
A uniform horizontal wire with a linear mass density of 0.48 g/m carries a 1.9 A current. It is placed in a constant magnetic field, with a strength of 3.5 10-3 T, that is horizontal and perpendicular to the wire. Neglect the magnetic field of the Earth. (a) As the wire moves ...

Mechanics (A level), Please help
Call the length of string below point B as h, then diagonal of triangle = a - h. angle to vertical of string = theta T + Tcostheta = W use pythagoras to find h (a - h)^2 = b^2 + h^2 so h = (a^2 - b^2)/2a and costheta = h/(a-h) = (a^2 - b^2) /(2a(a - [(a^2 - b^2)/2a] ) which re...

physics
A +5.7C X 10 to the -6 power point charge is on the x-axis at x=-3.0m,and a +2.0C X 10 to the -6 power point charge is on the x-axis at x=+1.0m.Determine the net electric field (magnitude and direction) on the y-axis at y=+2.0m.

Government
The Anti-federalists were against ratification of the constitution mostly because

science
Examine the obvious environmental impacts as well as significant social and physical ramifications of urban sprawl. What is the relationship between landscape and psychological well being? After defining this relationship, discuss how the presence or absence of natural beauty ...

science
Give examples of how humans have increased their food supply and what effects these methods have on the environment overall.

chemistry
how does the addition of a nonvolatile solute affect the vapor pressure of the solvent into which it is dissolved?

chemistry
2- A 0.310 M solution of a weak acid, HX, has a pH of 2.53 a. Find the [H+] and the percent ionization of nitrous acid in this solution. b. Write the equilibrium expression and calculate the value of Ka for the weak acid. c. Calculate the pH of the solution formed by adding 10...

chemistry
thank you!

Chemistry
need more help

Chemistry
need more help

math
The space station is going 17500 mph as it orbits the earth. How long will it take to orbit 1 time if the earths diameter is 7926 miles and the space station orbits at 240 miles above the earth.

Science
How many milliliters of water at 20.0 °C are formed in the combustion of 25.0 g of a methanol–propanol mixture that is 62.5% methanol by mass? Assume there is an excess of oxygen available.

chemistry
120.g NO

chemistry
How man grams of nitrogen monoxide are needed to react with adequate oxygen to produce 89.6 L of nitrogen dioxide

AQA Mechanics (M1), Statics and forces,please help
The diagram shows a cylinder of mass 20 kg lying at rest on two smooth planes inclined at angles of 40 degree and 50 degree to the horizontal. Calculate the reaction force exerted by the planes on the cylinder. For digram, please click the following link

chemistry
If HClO2 is a stronger acid than HF, which is stronger than HOCl, then the order of strengths of the conjugate bases of these acids is ______ < _____ < _____ a) ClO- < F- < ClO2- b) ClO2- < ClO- < F- e) F- < ClO2- < ClO- c) ClO- < ClO2- < F- d) Cl...

chemistry
The Ka for HOBr is 2.4 x 10-9. Thus, you can report the pKb for OBr– as a) 4.2 x 10-6 b) 9.62 c) 5.38 d) 8.62 e) 1.38 help!

chemistry
Which salt below will dissolve in water to yield an acidic solution? a) NaNO2 b) K C§¤O4 c) NH4NO3 d) Na2CO3 e) Mg Br2 help!

chemistry
The approximate pH of a 3.0 x 10-3 M solution of the strong acid H2SO4 is a) 3.5 b) 3.0 c) 2.5 d) 2.2 e) -3.0 how do you do this?

chemistry
The ion HPO4–2 has both a conjugate base as well as a conjugate acid. The conjugate base of this ion is (1) while the conjugate acid is (2). a) (1) = H2PO4– (2) H3PO4 b) (1) = PO4– (2) H2PO4+ c) (1) = PO4–3 (2) H2PO4– d) (1) = HPO5–3 (2) HPO3–...

chemistry
Which of the following is a Bronsted-Lowry base but not a Lewis base? a) H2O c) CN– e) all choices are both a B/L and Lewis base. b) CO3–2 d) NH3 need help deciding

chemistry
Which of the following is not amphiprotic? a)H2O c)NH4+ e)all choices are amphiprotic b)HSO4 – d)H2PO4– need help!

english
In The Secret, the secret is found in a a conversation. b letter. c line of poetry. d newspaper column. I think a

chemistry
Using this data, 2 NO(g) + Cl2(g) == 2 NOCl(g) Kc = 3.20 X 10-3 NO2(g) == NO(g) + ½ O2(g) Kc = 3.93 calculate a value for Kc for the reaction, NOCl (g) + ½ O2 (g) == NO2 (g) + ½ Cl2 (g) A. 20.2 B. 2.06 X 10-4 C. 4.49 D. 4.84 X 10-3 E. 0.223 eliminated down...

chemistry
Using this data, 2 NO(g) + Cl2(g) == 2 NOCl(g) Kc = 3.20 X 10-3 NO2(g) == NO(g) + ½ O2(g) Kc = 3.93 calculate a value for Kc for the reaction, NOCl (g) + ½ O2 (g) == NO2 (g) + ½ Cl2 (g) A. 20.2 B. 2.06 X 10-4 C. 4.49 D. 4.84 X 10-3 E. 0.223 eliminated down...

physics
A child moves with a speed of 5.40 m/s when positioned 14.0 m from the center of a merry-go-round. Calculate the net force (in newtons) exerted on the child, whose mass is 26.0 kg.

chemistry
when you reverse it do you get a negative?

chemistry
Using this data, 2 NO(g) + Cl2(g) == 2 NOCl(g) Kc = 3.20 X 10-3 NO2(g) == NO(g) + ½ O2(g) Kc = 3.93 calculate a value for Kc for the reaction, NOCl (g) + ½ O2 (g) == NO2 (g) + ½ Cl2 (g) A. 20.2 B. 2.06 X 10-4 C. 4.49 D. 4.84 X 10-3 E. 0.223 eliminated down...

Math
A bag has 4 red, 6 white, and 9 blue marbles. How many ways can 5 marbles be selected if 2 are one color, and 3 are another color?

PHi103
The truth table for a valid deductive argument will show

math
(4.35E-2 - x)(7.56E-2 -x ) ============================ (0.324 + 2x)2 Rearrange to get an expression of the form ax2 + bx + c = 0 and use the quadratic formula (solve for x. This gives: x = 1.05E-2, 0.143 basically i understand they use the quadratic equation but how did they...

physics
a 25000000 gr rocket is propelled from rest by an engine that produces a 312500 kgm/s2 for 1.375s A) What is the sleds acceleration? B) What is the velocity after 1.375s?

Math :(
please answer......

Math :(
A rectangular pyramid with the base of 12 feet by 8 feet need to be filled with balloons. if the pyramid 16 feet tall, how much space is available for the balloons?

math
the outlier is 7 and the outlier is a number away from all the other ones,which in this case is 7.

math
Jean has 4 times as many marbles as Peter. If Jean gave 18 marbles to Peter, they would then have the same number of marbles. How many marbles does each have?

Chemistry
How many moles of nitric acid will be produced when .51 mole of dinitrogen pentoxide reacts

7th grade math
yes,Pi is an irrational number.

math
Determine the slope of a line passing through the points (2, 9) and (0.66, 9).

physics
Jabdbal

6th grade science
How do the surface proteins on a virus help it to invade a host cell?

Math
Parallel lines have the same slope so the slope of 3x-4y+5 =0 is y=(-3x-5)/-4 slope =3/4 therefore the y=(n-2)x+12 must have a slope of 3/4 so n-2=3/4 n=2.75 If the lines are perpendicular they have negative reciprocal slopes therefore n-2= -4/3 n=2-4/3 or 2/3

algebra
There are three important numbers coming from the factors, 0, -1, and 3 test using numbers around those numbers. Using -2 because it is less than -1 (-2)(-2+1)(-2-3) =-10 which is < 12 Using -.5 because it is between -1 and 0 (-.5)(-.5+1)(-.5-3)=.875 which is <12 Using 1...

Physics help?
A 170 -pF capacitor is connected in series with an unknown capacitance, and as a series combination they are connected to a battery with an emf of 25.0 V. If the 170 -pF capacitor stores 135 pC of charge on its plates, what is the unknown capacitance?

maths
Do the same thing you did before using -1/2 for x. (2x+1=0 and solve for x) Then you will have two equations and two unknowns and you can solve for p

math
x= total marbles x-(1/4)x what he had after 1st round (x-(1/4)x)-1/3(x-(1/4)x) what he had left after 2nd (x-(1/4)x)-1/3(x-(1/4)x)-1/2((x-(1/4)x)-1/3(x-(1/4)x)) what he had left after 3rd round which equals 2 (the one he gave to Shavana and the one he kept) (x-(1/4)x)-1/3(x-(1...

Math
When raising to a power multiply the exponents. 8.8*10^25

math 2nd grade
francisco (:

3 grade math
You body consist of 7/10 water. Is more than 1/2 your body water? Explain

5th grade Math
-3+5*(2(-6))=37

Trig
A pilot is flying over a straight highway. He determines the angles of depression to two mileposts, 6.7 mi apart, to be 36° and 41°, as shown in the figure

One Trigonometry Question Please Help!
8 1/2 inches long into 1/2 inches long will be how many short pecies

One Trigonometry Question Please Help!
8 1/2 inches long into 1/2 inches long will be how many short pecies

Math
Words

Mathematics
What percentage is 2/27?

Physics
A 73kg sprinter, starting from rest, reaches a speed of 7.0 m/s in 1.8s, with a negliable effect due to air resistance. The sprinter then runs with the remained of the race at a steady speed of 7.0 m/s under the influence of a 35-N force due to air resistance. What is the aver...

Math
It equauls 2sinx

Math
How do I solve: sqrt(3)tanx= I need to use the identity tanx=sinx/cosx Thanks

chemistry
If the reaction Cl2 (g) + O3 (g) = Cl2O (g) + O2 (g) occurred in just two steps, what would be the overall order of the reaction be? a. 1 b. 2 c. 3 d. 4 e. not possible to determine from the information given help

chemistry
The equation A + 2 B = C + D describes an elementary reaction, which takes place in a single step. Thus, the rate law must be a. rate = k(A]2 b. rate = k(B]2 c. rate = k(A][B] d. rate = k(A][B]2 e. none of the above represents the rate law for this elementary reaction. help

chemistry
The decomposition of hydrogen peroxide in solution and in the presence of iodide ion was studied in laboratory, and the following mechanism proposed based on the experimental data. H2O2 + I - = H2O + IO - (slow) H2O2 + IO - = H2O + O2 + I - (fast) Which one of the following st...

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