Posts by vicky

Total # Posts: 293

physics
Determine the ionization energy required to extract the electron totally out of a hydrogen atom, and put it at rest

physics
The index of refraction of water for a given monochromatic light in water is n=4/3. The wavelength of this light in water is 500nm.  a) find the speed of this light in water.  b) find the energy of one photon of this light . Does this energy change if this light is ...

physics
The index of refraction of water for a given monochromatic light in water is n=4/3. The wavelength of this light in water is 500nm. a) find the speed of this light in water. b) find the energy of one photon of this light . Does this enerdy change if this light is propagated in...

Slope
Find the equation of the line that goes through (3,-4) with slope m=-1/4

math
In a club 15 members choose from them a president , secretary and a treasurer. How many different states of candidates can be chosen?

math
you have 6 marbles each of a different color . In how many ways can they be arranged in a row?

Math
750

math check my answer ?
What is the range of f(x)=?3x?1? the set of real numbers less than 0 the set of real numbers greater than 0 the set of real numbers greater than ?1 the set of real numbers less than ?1 <my choice

chemistry
The label of a bottle containing a solution So of hydrochloric acid carries the following indications :hydrochloric acid of density 1190g/l percentage by mass 37%. We introduce a volume V=4.2ml of So in a volumetric flask of volume 500ml containing about 100ml of distilled ...

chemistry
One has a solution Sa of ethanoic acid of concentration Ca=1×10^-2 mol/l and pH=3.4  One mixes a volume Va=60ml of the solution Sa of ethanoic acid with a volume Vb1=20ml of the Sb1 solution of ammonia of concentration Cb1=2×10^-2 mol/l. The pH is 5 One has a ...

chemistry
One has a solution Sa of ethanoic acid of concentration Ca=1×10^-2 mol/l and pH=3.4 One mixes a volume Va=60ml of the solution Sa of ethanoic acid with a volume Vb1=20ml of the Sb1 solution of ammonia of concentration Cb1=2×10^-2 mol/l. The pH is 5 One has a ...

chemistry
The label of a bottle containing a solution So of hydrochloric acid carries the following indications :hydrochloric acid of density 1190g/l percentage by mass 37%. We introduce a volume V=4.2ml of So in a volumetric flask of volume 500ml containing about 100ml of distilled ...

physics
A train travelling at 30km/h stops when it's brakes are applied. The train suffers a deceleration our 2m/s. @. How long does the train take to come to rest? b) what is its final velocity?

physics
I just need to know what formula i need to use

physics
In the circuit we have E=48V, R=6 ohm and L=4H. We close the switch at the instant t=0, the current I in the circuit grows from zero to its maximum value Io, and the permanent phase is established. A) determine the value of Io. B) calculate the values of the potential ...

physics
The self induced e.m.f created in a coil has the value of 24mV at the instant when the current is 4A and varies at the rate of 10A/s. What is the value of the self magnetic flux kn the coil at this instant?

chemistry
For the equilibrium: H2 + I2 <=> 2HI The equilibrium konstant Kc is equal to 50.5 at 448ºC. If [H2]o=[I2] o= 1 mol/l. What will the concentration of H2, I2 and HI be at equilibrium

science
HOW MANY ATOMS OF OXYGEN ARE PRESENT IN 8.8G OF CARBON(IV)OXIDE

physics
The characteristics of a horizontal and undamped spring-block system are k=400N/m and M=0.3kg.The position of the block is determined by its abscissa along an x'ox axis. When the spring has its natural length then x=0. a) the spring is stretched by shifting the block by 10...

chemistry
what is the type of catalyst that corresponds the use of the platinum wire

physics
A semi circular rail of horizontal diameter AB=2R is placed in a vertical plane. Two particles S1 and S2 of respective masses m1 and m2 (m1 <m2) slide without friction on the inner surface of this rail. A) Particle S1 is released at point B without initial velocity ....

physics
A rope of mass M uniformly distributed along its length L ,can slide without friction on a horizontal table. At instant to=0 the hanging part of the rope has a length b and the rope is held at rest .When it is left the rope begins to slide. At instant t the part of the rope ...

physics
A pendulum is formed of a particle of mass 100g suspended from the end of an inextensible string of negligible mass and of length L=100cm. The pendulum is shifted by an angle of 60 degrees from its equilibrium position about a horizontal axis passing through the other end of ...

physics
in part b we do G.P.E=E.P.E ?

physics
we launched a solid of mass m on an inclined slide. The natural length of the spring is Lo. Before launching, the spring is compressed to a length L. After launching the center of mass of the solid reaches the point A of altitude Z with velocity v. Neglect friction. a) ...

physics
A pendulum is formed of a particle of mass 100g suspended from the end of an inextensible string of negligible mass and of length L=100cm. The pendulum is shifted by an angle of 60 degrees from its equilibrium position about a horizontal axis passing through the other end of ...

physics
Two particles A and B of respective masses M(B) and M(A) are connected together by means of an inextensible string of negligible mass. The string passes over the groove of a pulley of negligible mass. At instant to=0 the system S(pulley,mass,string) is left without initial ...

physics
A particle C can move along a slide placed in a vertical plane. Points A and B are at the same horizontal level. Determine with respect to B the point where the velocity of C is zero for the first time in the three following cases: a) C is released from A without initial ...

One more Social Studies Help
Why did the British feel justified imposing the Stamp Act on the colonists? Select two. a. Similar stamp taxes were already used in England and Europe. b. The taxes protected colonists from Native Americans. *** c. Britain had spent money protecting colonists from the French...

Social Studies Help ASAP
Thank you. I just didn't trust with "kay." People outside of this tutoring community can lie to you. Again, thanks!

Can I REALLY have a professional's help?
Thanks.

Social Studies Help ASAP
Why did the British want to expand control into the Ohio Valley in the mid-1700s? a. to force the French out of North America b. to put French settlers there under English rule c. to demonstrate Britain’s strength to France and Spain d. to gain access to the region’s...

math
How much talk time if call costs 36 cents a minute and i have 30 dollars?

chemistry
How could you prepare: a ) 2-chloropropane from 2-propanol? b) 2-butanone from 2-butanol? c) ethyl acetate CH3COOC2H5 from ethanol? d) 2-methyl-2-butene from 3-methyl-2-butanol?

math
Let f be the function defined on {-3, 1} by f (x)= (x+1)/x^2+ax+b and (C) its representative curve in an orthonormal system . Knowing that the two lines of equations x=1 and x=-3 are asymptotes to (C) calculate the values of a and b.

Statics
Thanks Reiny

Statics
In a first semester unit there are four tests each of equal weight i.e. each worth 25%. Your average on the first three tests has been 62%. You need to get an overall average of 65% to proceed to the second semester. What percentage should you try to get on the fourth test? ...

math
A tank is 5/7 full, when 440 litres are removed it goes to 2/5. How much litres does it contain in full capacity

11th grade physics
The magnetic field strength along the axis (x'ox) of a solenoid is measured ( o being the center of the solenoid). The adjacent graph represent the length: (The graph represents the variation of B (mT) as a function of x (cm). The numbers on the y axis are 1 2 3 and on the...

plz help physics!!!!
A proton is moving in vacuum along a straight path from A to B .It passes point A at the speed of 2000km/s. a)Calculate in J and in eV the kinetic energy of the proton at A. b)Calculate the value of the positive voltage U that should be applied between A and B so that the ...

plz help physics
A proton is moving in vacuum along a straight path from A to B .It passes point A at the speed of 2000km/s. a)Calculate in J and in eV the kinetic energy of the proton at A. b)Calculate the value of the positive voltage U that should be applied between A and B so that the ...

Physics
q=cu find the charge of the first capacitor the find the equivalent capacitance of the parallel and q=c<?>(100) U(AB)=VA-VB

life orientation
Life orientation

physics
An air condenser has an area of 100 cm^2 the plates being 4mm apart. It is connected in series with another condenser having plate area of 20cm^2 plates being separated by dielectric 0.1mm thick with E=2.5. If the potential difference across an condenser is 1000volts; find the...

physics
An air condenser has an area of 100 cm^2 the plates being 4mm apart. It is connected in series with another condenser having plate area of 20cm^2 plates being separated by dielectric 0.1mm thick with E=2.5. If the potential difference across an condenser is 1000volts; find the...

geometry
Where are the angles

math
I guess you could do cross multiply but the first sentence wasn't clear

geography
A sea is a large body of salt water that is surrounded in whole or in part by land. More broadly, "the sea" is the interconnected system of Earth's salty, oceanic waters—considered as one global ocean or as several principal oceanic divisions...

chemistry
Consider an isomeric mixture of alkenes of molar mass M=70g/mol. Determine the molecular formula of the alkenes.

11th grade physics
Two point charges q and q' are placed respectively at two points A and B. Let O be the midpoint of [AB]. Charge q placed at A creates at O an electric field of strength E=9×10^6 V/m. Determine the resultant electric field at O when:  a) q'=q  ...

11th grade physics
Two point charges q and q' are placed respectively at two points A and B. Let O be the midpoint of [AB]. Charge q placed at A creates at O an electric field of strength E=9×10^6 V/m.  Determine the resultant electric field at O when:  a) q'=q  ...

11th grade physics
Two point charges q and q' are placed respectively at two points A and B. Let O be the midpoint of [AB]. Charge q placed at A creates at O an electric field of strength E=9×10^6 V/m. Determine the resultant electric field at O when: a) q'=q b) q'=-q

11th grade physics
Multiple choice (show your work if any):  1) Two point charges q1=-10^-5 C and q2=-9×10^-5 C are placed respectively at two points A and B 40 cm apart.   The electric field is null at a point C outside [AB] such that :  a) AC=50cm b) AC=30cm c) AC=20cm d) ...

Trig help
From my knowledge: #=alpha Sin: x=#+2kpi and x=pi-#+2kpi When u come out with the value of sine (alpha) you place it in the both cases and then you put it in the interval 0 <#+2kpi <2pi

11th grade physics
Multiple choice (show your work if any):  1) Two point charges q1=-10^-5 C and q2=-9×10^-5 C are placed respectively at two points A and B 40 cm apart. The electric field is null at a point C of [AB] such that :  a) AC=50cm b) AC=10cm c) AC=20cm d) point C ...

11th Grade physics
Multiple choice (show your work if any):  1) Two point charges q1=-10^-5 C and q2=-9×10^-5 C are placed respectively at two points A and B 40 cm apart. The electric field is null at a point C of [AB] such that :  a) AC=50cm b) AC=10cm c) AC=20cm d) point C ...

11th grade physics
Multiple choice (show your work if any): 1) Two point charges q1=-10^-5 C and q2=-9×10^-5 C are placed respectively at two points A and B 40 cm apart. The electric field is null at a point C of [AB] such that : a) AC=50cm b) AC=10cm c) AC=20cm d) point C doesn't ...

chemistry
The analysis of halogenated hydrocarbon gave the following results: A sample of mass m=255mg produces 273.7 mg carbon dioxide and 130.6 mg of water .A second sample of mass 87 is treated by hot molten sodium .The obtained mixture is dissolved in distilled water and filtered ....

english
The question is Explain the function of the first four paragraphs of the reading text The name of the text is The Machine Could Save Your Life by Malcolm Mcconnell

Social Studies
4 c 5 a or c

chemistry
25ml of 0.01M KIO3 solution were put to react with an excess of KI. 32.04ml of the sodium thiosulfate solution were needed to titrate the triiodide ions that were present . What is the molar concentration of thiosulfate in the solution?

maths
28 is divisible by 2 and also 90 28÷2 14 --- = --- 90÷2 45

Maths
Probability= #of favorable cases ------------------------ # total possible

physics
A disk is free to rotate around its fixed axis of revolution (delta). The moment of inertia of disk around delta is J=4×10^-2 kg.m^2 This disk is initially at rest is submitted to the action of a couple whose moment is equal to 0.2 N.m What's the ...

physics help please
y=1/2gt^2+vsin (35) y=1/2×10×2.7^2+15×sin (35) y=30.02m

Advanced functions
Find the area of a sector of a circle that has a central angle of 3π/8 and a radius of 7 cm.

chemistry help
A solution of thiosulfate ions has been prepared by dissolving 4.5g of Na2S2O3.5H2O in 250 ml of solution. Calculate the concentration of the thiosulfate ions S2O3^2- in the solution

math
how to calculate vertical angle of cone

math
how to calculate vertical angle of cone

English
How do i go about writing an essay whose topic is "Sports- General, types of fans and influence on culture?"It is under classification and division in Successful College Writing.

Homeschool
A ibc with no lid is made by cutting four squares if side length x from each corner of a 10 cm by 20 cm rectangle sheet of metal. Sketch the graph of the function and state restriction 250 200 150 100 50 -5. 5. 10. 15 -50 -100 -150 -200 -260

math
what is the global maximum of the parabola y= -x^2 -12x +4

math
(4n-1)^2=16

French
thank you

French
Whats the partitive article for Je n'ai pas gateau?

MATH
thank you

MATH
Mimo wishes to leave a waitress a tip. Mimo has five coins in his pocket, a penny, a nickel, a dime, a quarter, and a half-dollar. If he uses exactly three coins for the tip, how many different tips are possible? A. 15 B. 5 C. 20 D. 10 Crystal wants to put a fence around her ...

Math help
Mimo wishes to leave a waitress a tip. Mimo has five coins in his pocket, a penny, a nickel, a dime, a quarter, and a half-dollar. If he uses exactly three coins for the tip, how many different tips are possible? A. 15 B. 5 C. 20 D. 10

Math help
Sorry I posted the wrong answer I will post it again meanwhile can you help me with the second question thanks?

Math help
How many squares in this figure? (1 point) 4.) 15 5** 20 10** Crystal wants to put a fence around her vegetable garden.Her garden is 5 ft wide and 4 ft long.She plans to put a post at each corner and at every foot.How many fence posts will Crystal need? (1 point) 14 posts 18 ...

Language Arts
1.)Which of the following sentences contains parallelism? a.)We sold two bikes at the garage sale, and we also sold four chairs, as well as receiving offers for three lamps. b.)I prefer new things, but some people like to buy things that other people have owned. c.)A garage ...

social studies
Thank you Ms.Sue

social studies
Why did the British have problems after the French and Indian War? a.)they had less territory than before the war b.)they no longer had native american allies c.)they were faced with a devastating natural disaster after the war ended d.)they were left with a large public debt ...

nutrition
What is the answer to the rest

physics
a vehicle is accelerating on a straight road. Its velocity at any instant is 30 km/hr, after 2 s, it is 33.6 km/hr and after further 2 s, it is 37.2 km/hr. Find the acceleration of vehicle in m/s^2

math 1 question!!!!!!
c you idiot

American History
Which of the following statements is most accurate regarding America's political climate between 1876 and 1896? A. Southern states tended to vote Republican. (B.) The influence of the president over Congress diminished. C. The party that won the presidential election also ...

Social Studies
If you were a reform-minded person who, above all, loathed the social problems associated with alcohol, you would have been especially sympathetic to the A. Comstock Law. (B.) WCTU. C. Mugwumps. D. evangelical efforts of Dwight L. Moody. I chose B is this right?

math 6 probability
75 sorry

math 6 probability
the answer is 50

math
Telephone company A charges $3.00 for the first minute of any long distance call and $0.50 for each additional minute. Telephone company B charges $2.00 for the first minute of any long distance call and $0.70 for each additional minute. If the cost of a call lasting x minutes...

anatomy
For my anatomy class, I need a to make a human bone such as a femur or any other bones in the human body. Any suggestions on a website?

health care
It has to be a power point presentation on the cons of breaking bad news medically

health care
I have to do a debate on breaking bad news medically. I have the con side to it. Can you recommend some sites

english
I have to write a research paper on why ernest hemingway would be a good author for college students to ready. Any suggestions on where to start?

chem
Consider the following neutralisation reaction: 2 H3PO4(aq) + 3 Ca(OH)2 (aq) → Ca3(PO4)2 + 6 H2O Determine the volume of 0.75 M H3PO4 necessary to neutralise 35 ml of 0.45 M Ca(OH)2

math
Todds weight dropped from 220 pounds to 190 pounds. Cassidys weight dropped from 150 pounds to 135 pounds. Who had the greater percent weight loss?

math
the number of students at a university increases from 8000 in 1970 to 20,000 in 2000. what was the percent increase in enrollment from 1970 to 2000?

math
in a survey of 1,500 people who owned the same make of car, 600 indicated that they would buy the same make of car again. What percent of these people were satisfied with their car?

Math
It says the answer is 4800 but I don't know how they arrived at that answer

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