# chemistry! URGENT

59,982 results, page 13

### urgent

How much heat energy is required to raise the temp of 5 kilograms of coal from 20 degrees celsius to 220 degrees celsius? A 314 J B 6,573 J C 1,314,718 J D 4,187,000 J You asked this question already. See my other posted answer.

### algebra..urgent!!!!

MArta has $6000 to invest. She puts x dollars of this money into a savings account that earns 2% interest per year. With the rest, she buys a certificate of deposit that earns 4% per year. i need 2 different equations. [using a=prt and/or a=p(1+r/n)^nt]

### physics urgent!

A vaulter holds a 34.1 N pole in equilibrium by exerting an upward force U with her leading hand and a downward force D with her trailing hand. Point C is the center of gravity of the pole. Given d1 = 1.100 m, d2 = 1.65 m, and d3 = 2.75 m, what are the magnitudes of U and D? i...

### Calculus(urgent please help)

Consider the following function f(x)=x^2/[x^2-9] f(x) is increasing on the interval(s) f(x) is decreasing on the interval(s) f(x) has 2 vertical asymptotes x= f(x) is concave up on the interval(s) f(x) concave down on the interval(s) I've been stuck on these parts, I answered ...

### Physics 11 urgent Steve, bob, damon pls

A 30 kg student pushes a 20kg box on frictionless surface. If student accelerates at 0.8m/s^2(N),what is acceleration of bix. now why does the box acceerate towards south, if it is being pushed north should it not move north.

### Violence Action Plan (URGENT)

What are five or more different things students in school could do to prevent racism? 1. Multicultural Day could be one strategy. Students would be asked to bring in food samples from their culture. 2. 3. 4. 5. Can someone help? I only have one. Any help, suggestions are ...

### Biology (URGENT PLEASE!)

This is a question of my last biology test: Name at least one technological device that would have not been invented without scientific knowledge: A.Radio B.Ruler C.Knife D.None of the above I answered D but got a cross for it. So can you please help me to solve what is the ...

### math-college URGENT**

in sentence form using one variable and one equation/inequality solve: sue makes $15/hour tutoring and averages $10/hour waitressing. Out of 30 hrs working time, what is the minimum # of hours she should tutor if she is to make at least $475?

### URGENT Physics help

An attractive force of 7.2 N occurs between two point charges that are 0.10 m apart. If one charge is 4.0 µC, what is the other charge? (µC = 1.0 × 106 C) (Points : 3) 1.0 µC 2.0 µC +1.0 µC +2.0 µC Which substance is most easily grounded? (Points : 3) plastic foam plate...

### physics(urgent answer pls)

A projectile is launched with 30m/s at an angle of 60degree with d horizontal (a) find d position of the projectile,and d magnitude and direction of its velocity at t=2s (b) find d time when d ball reaches the highest point (c) find d horizontal range

### Math

You wish to paint your room. It's four walls measures 9ft high and 10ft wide. If one gallon of paint covers 120sq. ft, how many gallons of paint will you need? Please help?!!! Need this. Urgent.. With solutions please 🤖

### calc(very urgent)

Imagine a flat-bottomed cylinderal container with a circular cross section of radius 4 in. a marble with radius 0<r<4 inches is placed in the bottom of the can. what is the radius of the bottom that requires the most water to cover it. (include first or second derivative...

### chem urgent!!

At a temperature of 35 °C, fluorine gas effuses through a pinhole at a rate of 8.7 L s−1. What is the speed of the fluorine as it effuses through the pinhole? i no u use the eq. 3rt/M ^.5 but i get 20 for the answer but it is really 450.

### APCHEm urgent!!!!!!

Hi thank you so much!!!! What is a net ionic equation for the reaction of H+ with Cu(NH3)4 ^2+ ALSO what is the net ionic equation for the reaction of H+ with Hg2Cl2 Does the H+ addition increase, decrease, or has no impact on the solubility of the salt.?

### Calculus(Urgent help)

f(x)=x^3-3x^2+3x+1 near 2 (at a=2) A. Use Linear approximation to approximate. b.is this underestimate or overestimate? Justify answer. C.Approximate f(2.25) using the linear approximation and compare the answer with the exact value. Thanks.

### English 10

I have to a narrative argument about the human nature in the book Lord of The Flies. Any ideas what examples of human nature in the book i can use? please help this is urgent. Please!!

### Math - Urgent

The air temperature is -10 degree Celsius. With the wind blowing at a speed of 15 km/h, this temperate feels like -17 degrees Celsius. How many degrees does the temperature change because pf the wind chill?

### History (urgent!)

Hi, I was wondering what a princess's job in the community was...I would prefer specific links to sites--that would be very helpful! Also, I need to know why a princess's job is important to the community. Thank you so much!! :)

### Physics - URGENT

The seventh harmonic of a one end closed pipe organ has a frequency of 732 Hz, on a day when the temperature is 10 degrees Celsius. How long is the pipe? How long would it be for 732 to be the first harmonic?

### Physics Urgent

In a uniform magnetic field, can an Amperian loop ever have a non-zero value of its line integral with the magnetic field? a)yes b)No, it will always be zero c)depends on the orientation and shape of the loop.

### Math- urgent

Solving Systems by Substitution Maribel has $1.25 in her pocket. The money is in quarters and dimes. There are a total of 8 coins. How many quarters and dimes does Maribel have in her pocket? I think the equation is 10x+25x=$1.25 and x+x=8 but I'm not sure.

### PHYSICS URGENT! PLEASE FRICTION CASE 2

A 13 kg box is at rest on a level floor. The coefficient of static friction µS = 0.9 and the coefficient of kinetic friction µK = 0.8. Audrey is applying a 140 N push at an angle (=20°) as shown in Figure 1. C) What is the magnitude of FNormal on box from Earth?

### URGENT

An urn contains a total of 9 marbles out of which 2 are red, 3 are white, and the remaining are blue. Two marbles are drawn out of the urn in succession. What is the probability that both marbles are the same color if: a. Replacement is allowed? b.The first marble is not ...

### calc Urgent please

A boat heads 15 degrees west of north with a water speed of 3m/s. Determine its velocity relative to the ground when there is a 2m/s current from 40 degrees east of north. How long does it take to cross the river which is 800 m wide? Where does the boat land on the other side?

### calculus

Find the dimensions of the right circular cylinder of greatest volume which can be inscribe in a right circular cone with radius of 5 inches and a hieght of 12 inches(hint:use similar triangle property).also draw a label diagram....plz answer its too urgent

### Socials (URGENT)

Why did the canadian government feel the need to control the economy, transportation and trade after war was declared in 1914? Was this a genuine need? Explain. Hi, I need some help on the second half of the question. Was it a genuine need? I can't find the answer anywhere. ...

### Physics Urgent please help

A man of mass 70 kg is in free fall in the air. He reaches a terminal speed of about v_term = 54 m/s. (Note that v_term >> v_crit and we are in the pressure dominated regime where F_fric is directly propotional to v^2 ; we have g = 9.8 m/s ) What is the force (in N) due ...

### PPPL THIS IS URGENT ITS HISTORY

1) Describe England post Henry VIII 2) Identify what Edward VI Did 3) Describe the affects on ENGLAnD WHILE HENRY THE VIII WAS RULING

### Precalculus(URGENT)

solve the problem 2xcubed-17xsquared+31x+20 given that 5 is a zero of f(x)= 2xcubed-17xsquared+31x+20 you can use lobng division or synthetic division

### math urgent please

How many league matches were played, write an algebraic expression to denote the number of league matches between the teams, if the number of teams is n.

### Maths (URGENT)

The values for x when f(x) = 0 are: x=-2 and x=3 My question is: The function f(x) can be written in the form of a(x-p)(x-q)(x-r) Write down one possible set of values for p, q, and r? Now Ive got the correct answer x = -3, 2 and 2 Could you show me step by step how I got that...

### math URGENT

okay i need to find the domain and range of this z(x) = ãx^2 - 100 (everything is in the square root) so i think i found the domain i got [-10,10] but i don't know about the range i solved for x and got stuck here x=ãy^2 + 100 helppp pleaseee :)

### maths urgent

1/5 of J's money is equal to 1/3 of S's money. The difference in their amount is 1/2 of A's money. If Adam gives $120 to S, S will have the same amount of money as J. How much do the 3 people have altogether?(please show me a model method, not algebra)

### URGENT! PLEASE HELP QUICK PHYSICS

Summarize two observations that are contrary to the predictions based on Newton’s laws but that confirm Einstein’s explanation of gravity. Indicate how the predictions based on Newton’s theory differ from Einstein’s.

### math (urgent )

13.875-0.1875(56.375)/8-2 (1/8+27.125/300.875 the answer is 1.1908 but when i calculate use calculator i cant get the answer.we need solve value in the bracket first then multipe by first value or how ? pls

### Economics

Hi, would anyone please help me with this question for economics. It for an assignment due in several days, and it is very urgent, because I cant information about it, and our school teacher in absent until the day it is due. thank you Trade unions and Employer Organisations, ...

### SPANISH 3 URGENT!!!!!!!!!

combina las palabras lógicamente. 1. la langosta 2. la salchicha 3. el ají 4. el caldo 5. el sacacorchos 6. hornear 7. los ingredientes 8. la sal 9. el durazno 10. el aderezo a. el vino b. la toronja c. la sopa d. la receta e. la pimienta f. la ensalada g. el pimiento h. ...

### SCIENCE URGENT HELP

what are the benefits of copper to the industry, economy, and society? what are all the organisms that are affected by copper? what is meant by the term Bioaccumulation? Include the names of any organisms that are affected and how they are affected by copper? pLEASE HELP ME ON...

### Calc 2 Urgent Surface Area of Revolution Question

Find the area of the surface generated when y=4x and x=1 is revolved about the y-axis. We have to use the surface area formula of revolution. Integral (2pi*f(x)sqrt(1+f'(x)^2))dx

### science..urgent!!

Describe what happens at the particle level and what happens to a liquid's temperature when it reaches the liquid's heat of fusion. Is it possible for the ice in your freezer to be below 0 degrees celsius? explain. When does ice in your freezer reach equilibrium?

### English Language

I asked this question earlier. I need to write 2 letters of complaint about problems I face at school and problems I face as a student in general but I can't find any problems, could you help me list some problems? Its really really urgent.

### math(Urgent)

1) The number of bacteria N in a culture is given by N=250e^kt where t is the time in hours. If N = 280 when t=10 estimate the time required for the population to double in size. 280 = 250e^10k divide by 250 1.12 = e^10k ln 1.12 / 10 = .011 K = 0.11 Now I do not know what to do!

### math(Urgent)

1) The number of bacteria N in a culture is given by N=250e^kt where t is the time in hours. If N = 280 when t=10 estimate the time required for the population to double in size. 280 = 250e^10k divide by 250 1.12 = e^10k ln 1.12 / 10 = .011 K = 0.11 Now I do not know what to do!

### physics urgent helppp!!!

A rocket of mass 4.50 105 kg is in flight. its thrust is directed at an angle of 49.0° above the horizontal and has a magnitude of 6.00 106 N. Find the magnitude and direction of the rockets acceleration. Give the direction as an angle above the horizonal.

### math urgent

In an election Ram and sham were two candidates. Ram got 54% of the votes cast and secured the majority of 250 votes. If none of the votes cast were invalid, find the number of vote cast?

### math VERY URGENT AND IMPORTANT

Estimate the product of 1 9/10 and 15. Describe your method. Also,estimate the product of 3 7/8 and 25. Describe your method. Please answer and explain.

### Quick Help (urgent)

How do you know the information presented on the sites are accurate? healthunit . com teenwire . com sexualityandu . ca sexetc . org I don't know how to do this question. Truth is I "don't" know if the information is accurate. Please help, like give me an example of how I can ...

### maths urgent please

a particle moves in a straight line such that its position x from a fixed point 0 at time 't' is given by x= 5 + 8sin2t + 6cos2t 1. Find the period and amplitude of the particle. 2. Find the greatest speed of the particle. Could you please explain the steps on how to get to ...

### Business communication

Pls! I need an urgent response my mentors. It is the ability of communication to foster speedy passage of information around that has shrunk the world and make globalisation a reality. In light of the statement above, what role does communication plays in the business world?

### Physics - urgent, please help!

10pm. I asked "Show mathematically that to produce an image that is the same size as the object in a concave mirror, the object needs to be at twice the focal length from the mirror." and bobpursley answered: "1/o + 1/o=1/f 1/2f + 1/i=1/f 1/i=1/2f i=2f M=di/do= 2f/2f= 1 check ...

### calculas(URGENT..... PLEASE....)

1) A region is bounded by the line y = x and the parabola y = x2 - 6x + 10. What is the volume of the solid generated by revolving the region about the x-axis? would u please give the explanation with a detailed steps to the answer because i am not able to reach the final ...

### physics (urgent)

A cricket ball is thrown at a speed of 30ms^-1 in a direction 30 degrees above the horizontal. Calculate: 1. The maximum height. 2. The time taken to return to the same level. 3. The distance from the thrower to where the ball returns to the same level. Posted this yesterday ...

### physics urgent

a metal sample carrying a current along X-axis with density Jx is subjected to a magnetis field Bz(along z-axis). the electric field Ey developed along Y-axis is directly proportional to Jx as well as Bz. the constant of propotionality has SI unit. 1. m²/As 2. m²/A 3.As/m³ ...

### Physics(Urgent)

Using Planck's constant as h=6.63 E-34 J*s, what is the wavelength of a proton with a speed of 5.00 E6 m/s? The mass of the proton is 1.66 E-27 kg. Remember to identify your data, show your work, and report the answer using the correct number of significant digits and units. m...

### URGENT Statistics

In performing two-tailed hypothesis test with v=20, you obtain a t-statistic of 2.41. The p-value is: Between 2% and 5%. I need help understanding how this range was gotten. I know that the t-statistic is between t.025 and t.01 and since this is a 2-tailed test these t-values ...

### math URGENT!!!!!!!

a rectangular sheet of paper is folded in half, with the crease parallel to the shorter edge. it happens that the ratio of longer side to shorter side remains unchanged. what is this ratio? answer this and explain how u got the answer.. PLEASE??!

### Algebra help URGENT Please?

Chris and five of his friends go out to dinner. The total bill comes to $124.29. They decide to leave a 20% tip. Each person will contribute an equal amount to the total tip. Estimate what each person should contribute. a$29.00 b$21.00 c$5.00 $4.15

### Physics 11 URGENT STEVE OR BOB OR ANY PHYSICS Guys

An 42 kmph wind blows towards 215 degrees while a plane heads towards 125 degrees at 152kmph. What is the resultant velocity of the plane? tenks vry much!!!!!!!!!!!!!!!!!!!

### Math - Urgent!

Can you show that you can share a square pizza equally between two people by cutting it four times using vertical, horizontal and diagonal (45 degree cuts) through any point inside the square? If you could give an explanation as well as an answer I'd be very grateful! I'd like...

### Urgent math

Two polynomials P and D are given. Use either synthetic or long division to divide P(x) by D(x), and express the quotient P(x)/D(x) in the form P(x) D(x) = Q(x) + R(x) D(x) . P(x) = 10x3 + x2 − 21x + 9, D(x) = 5x − 7 P(x) D(x) = 2x2+3x Incorrect: Your answer is ...

### science-VERY URGENT

I think it's A or C, but I need to know because it's due in an hour. Please help thank you, it's my last question on the homework. A flower is red, has a long tube formed by fusion of petals, has nectar at the bottom of the tube, has no landing platform, and opens during the ...

### WB (URGENT)

I've searched and searched but can't find any pictures that would depict a webmaster well. Can someone help me find a picture(s) that will depict a webmaster clearly. Please help. Thank you.

### Chemistry URGENT/DR BOB

Can someone may sure that I balanced the following groups of equations correctly. Write an equation to show how acetic acid reacts with water to produce ions in solution. C2H4O2 + H2O >>>>>>> H3O + C2H3O Write an equation for the neutralization of HCl and ...

### English... Urgent

Look at the following puzzles and try to decipher the well known sayings 1. Ban ana 2.nafish nafish 3.japmadean 4.issue issue issue issue issue issue issue issue issue issue 5. Lookuleap Note that I have not typed any of these words wrong

### math

Find the values of theta (0,2pi) that satisfy sin theta= square root 3 over 2 Solve 2costheta sintheta-sintheta on (0, 2pi) please I really need help in knowing how to solve these questions. quite urgent. I don't understand how to do them at all.

### Science urgent help please:)

Compare the forms of locomotion used by the 4 phyla of animal like protists? Describe the process of conjunction . Is conjunction a form of reproduction? Explain In what ways are animal like protists helpful to other living things?

### physics help needed very urgent !!!

The figure shows four penguins that are being playfully pulled along very slippery (frictionless) ice by a curator. The masses of three penguins and the tension in two of the cords are m1 = 10.5 kg, m3 = 14.7 kg, m4 = 22.05 kg, T2 = 120 N, and T4 = 236 N. What is the mass of ...

### Minimum Concentrations - Urgent help!

What is the minimum concentration? Determine the minimum concentration of the precipitating agent on the right to cause precipitation of the cation from the solution on the left. 8.0 x 10^-2 CaI2, K2SO4 1.5 x 10^-3 AgNO3, RbCl The Ksp values for both are Ksp = 2.4*10-6 for ...

### Physics-urgent

A speeder is driving down the road at a constant 20 m/s, he passes a patrolman parked on the roadside. The patrolman waits 3 seconds, then pursues the speeder, accelerating at a constant 4.0 m/s. How long does it take the patrolman to catch the speeder? How far has he traveled...

### physics urgent please help!

way safety engineers build soft barriers so that cars hitting them will slow down at a safe rate. A person wearing a safety belt can withstand an acceleration of 300 m/s 2 . How thick should barriers be to safely stop a car that hits the barriers at 81.7 km/h? Answer in units ...

### chemistry URGENT

I need someone to check my answers to make sure that I have the correct answers. (3 Part Question) Two students each measure the density of a quartz sample three times: Student A Student B 3.20 g/mL 2.82 g/mL 2.58 g/mL 2.48 g/mL 2.10 g/mL 2.59 g/mL mean 2.63 g/mL 2.63 g/mL 1. ...

### maths-urgent

rewrite the addition sum given below using digits. Each letter is used for a different digit. Answer the questions given below i) Which digit did you find first? ii) How did you find R and U? ........F.O.U.R ...........O.N.E ....T.H.R.E.E ....T.H.R.E.E _________ E.L.E.V.E.N ...

### maths-urgent

rewrite the addition sum given below using digits. Each letter is used for a different digit. Answer the questions given below i) Which digit did you find first? ii) How did you find R and U? ........F.O.U.R ...........O.N.E ....T.H.R.E.E ....T.H.R.E.E _________ E.L.E.V.E.N ...

### Algebra 2 URGENT

Solve the problem. Round the answer to the nearest hundredth. Please Show All Work! A garden is currently 4 meters wide and 7 meters long. If the area of the garden is to be doubled by increasing the width and length by the same number of meters, find the new dimension of the ...

### PHYsics URGENT

the deepest part of the ocean is 10,900 meters deep. a) calculate the absolute pressure at that depth in units N/m^2. Use the mass density of sea water, 1030 kg/m^3. see part b for more info b) one atmosphere of pressure is about 1.013 X 10^5 N.m^2. How many atmospheres is the...

### English

Can you briefly chech these few sentences, please? Thank you very much. They are urgent. 1) Dorian's wish for eternal beauty and youth could be connected to Goethe's Faust. 2) The portrait returns beautiful as original (or as it originally was?) 3) I didn't drink because I ...

### URGENT MATH please

Chris cuts half a rectangular lawn, 40m by 30m, by mowing strips of equal width around the perimeter. Jerri cuts the small rectangle in the middle that's left. How wide a strip does Chris cut so that they share the work equally? Solve by using quadratic formula.

### physics urgent

I need help with this problem. I know the answer is (2.1630342940) but I have no idea how to get there. I know i need to sum the forces for each. Block m1( 6 kg ), lies on an incline plane with a coefficient of kinetic friction of 0.15. m1 is connected to mass m2 by a massless...

### physics urgent please asnwer it i m begging u

a metal sample carrying a current along X-axis with density Jx is subjected to a magnetis field Bz(along z-axis). the electric field Ey developed along Y-axis is directly proportional to Jx as well as Bz. the constant of propotionality has SI unit. 1. m²/As 2. m²/A 3.As/m³ ...

### URGENT~MATH For Steve or Reiny

For questions 5-7, find the solution to the system of equations by using either graphing or substitution. 5)y=6-x and y=x-2 (1point) (2,4) (-4,2) (4,2) no solutions 6)y=2x-1 and y=x+3 (1point) (4,7) (7,4) (-7,-4) no solutions 7) y=4x and y+x=5 (1point) (-4,1) (1,4) (-3,2) (2,3...

### math

1. The x-intercept of a line is -3. The y-intercept of a line is 6. What is the slope of the line? 2. What is the equation in slope-intercept form of the line described in Exercise 1? can you please explain and answer it?? im having lots of trouble with this. it's urgent... ...

### PHYSICS(URGENT)

A particle has a mass of 5kg. It is held at a height of 3 metres above the ground. Find: a.Its potential energy b.It’s kinetic energy when is hits the ground c.The speed with which the particle hits the ground

### physics. urgent answer please

Two forces 10 N acting in the direction N 30 east and 15 N acting in the eastern direction, if both forces act at a point, find the magnitude and direction of (a) the resultant force (b) the equilibriant force.

### Needs Urgent Biology Help!

This all about plasmids: I am totally lost, and my notes/textbook/internet doesn't give me the answer to this. Thanks for the help! Q: How is the number of fragments produced associated with the number of cut-sites available to a restriction enzymes? Q: Why do all the fragment...

### Needs Urgent Biology Help!

This all about plasmids: I am totally lost, and my notes/textbook/internet doesn't give me the answer to this. Thanks for the help! Q: How is the number of fragments produced associated with the number of cut-sites available to a restriction enzymes? Q: Why do all the fragment...

### Needs Urgent Biology Help!

This all about plasmids: I am totally lost, and my notes/textbook/internet doesn't give me the answer to this. Thanks for the help! Q: How is the number of fragments produced associated with the number of cut-sites available to a restriction enzymes? Q: Why do all the fragment...

### Chemistry (URGENT)

I have a test soon. If you can help me with these questions, that would be great. 1. Define and describe the following. a)Alkaline - metal - base b)Corrosive - burn/eat away - acid c)Caustic - harsh - both? (acid + base) d)Low pH - 0-6.99 - acid Please check my answers and ...

### Urgent math

how do I do this can any body show me how? An arithmetic sequence begins 4, 9, 14, 19, 24, . . . . (a) Find the common difference d for this sequence. d = (b) Find a formula for the nth term an of the sequence. an = (c) Find the 35th term of the sequence. a35 =

### Chemistry Science Project

I need some ideas for high school science projects. It doesnt really matter what field of science, but i would prefer chemistry, biology, or physics. Really Urgent! Thanks! What about a project on osmotic pressure. Put a salt solution inside a thistle tube, place a membrane ...

### English/ History-Urgent

Was there a person in history whose personality changed dramatically in his/ her life? Who was he/ she? I did google search but still had no ideas? Can someone please give a name of person who changed dramatically in history? Any help will be appreciated. Thank You.

### algebra URGENT HELP

form a polynomial whose degree and zeros are given. don't expand a) degree 3,zeros,-2,0,4 b)degree 4,zeros, -2 multiplicity 3,1 multiplicity 1 solutions a)p(x)= x(x+2)(x-4) B)p(x) =(x+2)^3(x-1)

### HELP URGENT Phyiics

What mass (in grams) of steam at 100°C must be mixed with 446 g of ice at its melting point, in a thermally insulated container, to produce liquid water at 65.0°C? The specific heat of water is 4186 J/kg·K. The latent heat of fusion is 333 kJ/kg, and the latent heat of ...

### Physics pls anyone can help me? its urgent

Four charges are arranged at the corners of a regular tetrahedron (a pyramid with four sides that are identical equilateral triangles). The charges are 1 Coulomb each, and the sides of the tetrahedron are all 1 meter. How much energy in Joules is required to assemble this ...

### calculus (please help. URGENT!)

A hemispherical tank with a radius of 10m is filled from an input pipe at a rate of 3m^3/min. How fast is the water level rising when the water level is 5m from the bottom of the tank? (hint: the volume of the cap of thickness of h sliced from a sphere of radius r is pih^2(3r-...

### Urgent help here! Math

If 270kg of corn would feed 42 horses for 21 days, for how many days would 360kg of it feed 21 horses?

### music urgent!!!!!!!!!!!!

i need help with annotating a piece of idian bollywood music is there anyone who can help me? xXx uzi xXX hi hi back can can you help me with my music course work that is left before it is complete??? xXx uzi xXx

### Urgent english help

I'm writing an English persuasive essay and I'm wanting to put a quote from a person as the thesis. How would I quote it? Do I quote it then put the name of person in parentheses? Please help me thanks!

### 2 questions really urgent

sorry i have 2 more questions: what happens when a contour line crosses a river: stays flat, bends upstream , stops why do contour lines never cross eachother: they each represent a different elevation, the map would be too confusing, you cant tell the shape of the land please...

### physics urgent help !

if a 3e charge is at the origin and a magnesium nucleus is 3 cm from the originin the x-axis direction.what is the magnitude of the net electrostatic force a Boron nucleus would experience at the point half way between magnesium nucleus and 3e charge on the y-axis in N