# Posts by john

Total # Posts: 8,426

chemistry
Draw the dominant Lewis structure for NO2+. Note, that this ion is isoelectronic with CO2. How many double bonds does this resonance structures have?

chemistry
Draw one of the Lewis structure of the N2O5. In each case one oxygen bridges the nitrogens (N-O-N single bond) and 2 other oxygens are bonded to each N. How many equivalent resonance structures are there that satisfy the octet rule and where O makes at most 2 bonds?

Chemistry
How do we use 2 indicators to confirm the pH of a solution?

Fraction
A fruit grower uses 1/3 of his land for bananas,3/8 for pineapples1/6 for mangoes and the remainder for oranges. What fraction of his land is used for oranges?

Fraction
A girl spends 1/4 of her pocket money on monday and 3/8 on wednesday. What fraction of her money is left

Algebra 2
Telephone numbers are made of 7 digits. Digits can be repeated but the first digit cannot be 0 or 1. How many different telephone numbers can be created? I believe you use combination function, but I am not sure how and where.

Algebra check?
ok it wont let me put spaces, sorry! 1. 3i - 10 over 8i - 5 Answer: 74 over 89 + 65 i over 89 2. 11i^2 + 1 over -12i - 8 Answer: 5 (2 - 3 i) over 26

Algebra check?
Sorry the first post formatted weirdly. 1. 3i - 10 --------- 8i - 5 Answer 74 65i ---- + ----- 89 89 2. 11i^2 + 1 ------------ -12i - 8 Answer: 5 (2 - 3 i) ------------- 26 3. square root -25 * 8 square root -49 Answer: -280 4. square root -64 + 12 square root -36 Answer: 80 i...

Algebra
(sorry this formatted weirdly, it's meant to be this if you can't tell) 1. 3i - 10 over 8i - 5 Answer: 74 over 89 + 65 i over 89 2. 11i^2 + 1 over -12i - 8 Answer: 5 (2 - 3 i) over 26

Algebra
Can you tell me if my answers are correct for these problems? 1. 3i - 10 --------- 8i - 5 Answer 74 65i ---- + ----- 89 89 2. 11i^2 + 1 ----------- -12i - 8 Answer: 5 (2 - 3 i) ------------- 26 3. square root -25 * 8 square root -49 Answer: -280 4. square root -64 + 12 square ...

physics
The average car today has a mass of 1100 kg, and when accelerating from rest, covers 0.25 miles in 15 seconds. Each rim and tire together has a diameter of 45.7 cm and a mass of 9.1kg. How many revolutions did one of the front tires (assuming only the back tires spun upon ...

math
let f(x)=-5x+6 find and simplify f(x+2) f(x+2)=___

ap chem
Under certain conditions, the reaction 3 A + 4 B → 5 C is observed to proceed at a rate of 0.0106 M · s−1. What is the corresponding rate of change in product C? 1. 0.0318 M · s−1 2. 0.0106 M · s−1 3. 0.00353333 M · s−1...

physics
Find the x- and y-coordinates of the center of gravity of a 4.00 ft by 8.00 ft uniform sheet of plywood with the upper right quadrant removed as shown in the figure below. The dimensions of the cutout are a = 4.50 ft and b = 1.70 ft. HINTS: Think of the board as being made of ...

AP Physics C
A 4.10 kg block is pushed along a floor by a constant applied force that is horizontal and has a magnitude of 39.0 N. Figure 6-26 gives the block's speed v versus time t as the block moves along an x axis on the floor. What is the coefficient of kinetic friction between ...

Physics
A hiker hikes in a straight line and maintains a constant velocity of +0.5 m/s. At time t=0.0 s, the hiker is 30 m from point A. What is the displacement from point A at 120 s? a. 60 m c. 120 m b. 90 m d. 15 m

physics
thank you so much !!

physics
Two people (from the 1950s!) sit on opposite sides of a uniform board of length L. One person, of mass m1 = 50.0 kg, sits at a point 1.90 m to the left of the fulcrum. The fulcrum is located at the center of the board. The other person, of mass 45.0 kg, sits at a point a ...

Calculus
The top of a 13 foot ladder is sliding down a vertical wall at a constant rate of 4 feet per minute. When the top of the ladder is 5 feet from the ground, what is the rate of change of the distance between the bottom of the ladder and the wall

physics
A person is kayaking in the ocean at 5.6 m/s 75° to the horizon when he experiences a current of 3.8 m/s 45° south of west. What is the speed and direction of his kayak?

mathematics
the lenght of a rectangle is twice its width.If the width is reduced by 1cm and the lenght is also reduced by 2cm,the area will be 15cm(square).Find the dimensions of the original rectangle.

maths
A deck has 52 cards it has 13 in each type find the probability of getting a) a diamond card b) an ace card c) a red card d) a yellow card e) getting any card

English II
Compare the literary and rhetorical devices in Elie Wiesel's Nobel Peace Prize Acceptance Speech and his novel Night. Explain how these elements impact tone and mood. Support your claims with evidence from the text.

physics
A baseball is thrown at an angle of 20◦ relative to the ground at a speed of 25.6 m/s. The ball is caught 42.9416 m from the thrower. The acceleration due to gravity is 9.81 m/s2 . How long is it in the air?

world history
How did Europe’s geography/advantages lead to its rise as a global power?

physics
A triple beam balance, like the scales we use every week in lab, works using rotational equilibrium. If a 253 g mass is placed on the pan, 1 cm from the pivot, and there are three masses, 1 g, 10 g, and 50 g masses on the other side can be slid back and forth between 0 cm and ...

Human Relation - HELP!!!
Why parents considered as our role models?

Math

Math
A plane takes off from a local airport. It travels due north at a speed of 400km/h. The wind blows the plane due east at a speed of 50 km/h. How far is the plane from the airport after 1h. Give your answer to one decimal place

Math
I Cant tell you the answer. you should be able to figure the answer by yourself. ill be glad to check your work

Basic Statistics
A researcher is interested in estimating the average salary of police officers in a large city. She wants to be 95% confident that her estimate is correct. If the standard deviation is \$1050,how large a sample is needed to get the desired information and to be accurate within...

Basic Statistics
A random sample of 16 mid-sized cars tested for fuel consumption gave a mean of 26.4 kilometers per litre with a standard deviation of 2.3 kilometers per litre. (a)Assuming that the kilometers per litre given by all mid-sized cars have a normal distribution,find a 99% ...

Statistics
The points of 100 children in a test are normally distributed with mean of 25 points and a standard deviation of 10 points. (a)Given that the passing mark is 20, estimate the number of children who passed the test. (b)If 5.59% of the children obtain a distinction by scoring x ...

Sales
Indeterminate

Math
A water tank will be drained at a constant rate of 42.4 liters per hour starting at 9:00 A.M. After one hour, the change in the amount of water in the tank can be represented as –42.4. Which of the following represents the total change in the amount of water in the tank ...

math
how do i work this problem 8x25x23 using subtraction in mental math

physics
A truck with mass 2000 kg tows a boat and trailer of total mass 500 kg. The rolling coefficient of friction for the truck is 0.080 and for the trailer is 0.050. The force of the truck’s drive wheels pushing backward on the pavement is 3.0 kN. (a) Determine the ...

Math
If john makes 60 k a year , how much does he make each month?

Chemistry
Cambridge uses FA 1, FA 2 etc to name chemicals or solutions. What does FA stand for?

physics
12

physics
Two crewmen pull a boat through a lock, as shown in Figure 5-25. One crewman pulls with a force of F1 = 155 N at an angle of θ = 32° relative to the forward direction of the raft. The second crewman, on the opposite side of the lock, pulls at an angle of 45°. With...

Physics
A pilot gets into trouble flying 2000m above the pacific ovean. He flies 550 km/h [S 30(degree)W] with a wind from the NW of 100 km/h. he ejects himself at a velocity of 10m/s [upwards]. What is his velocity at the instant he hits the ocean surface? Express your answer in km/h.

physicss
If there were no air resistance, with what speed would drops hit the Earth if they fell from a cloud 1980 m above the Earth’s sur- face? The acceleration of gravity is 10 m/s2

Physics
A toy gun uses a spring to shoot a ball with a mass of 5.0 g. The spring is “loaded” by compressing it 5.0 cm and has a spring constant of 288 N/m. The end of the spring is at the end of the gun (the ball does not travel any distance inside the gun after the spring) ...

Empirical Inquiry
Assume that true proportions of the people who support "Obamacare" is a quarter of the population. If you took a sample of 1,000 people living in the United States, what would be the variance of this estimator? what would be the expected value of your estimator for ...

Math
In this problem, what do you have to do because you just wrote something but didn't explain how this is suppose to be done

physics
im sorry but i cant tell you the answer ill be gladly to check though

math
2/5(x+3)=6 2/5x+6/5=6 5/2(2/5x) +6/5 = 6(5/2) X+6/5=15 X-6/5=15-6/5 X=

College Math
A block with a mass of m = 31 kg rests on a frictionless surface and is subject to two forces acting on it. The first force is directed in the negative x-direction with a magnitude of F1 = 11 N. The second has a magnitude of F2 = 22.75 N and acts on the body at an angle θ...

Pre-Calculus

Pre-Calculus
Some cowboys plan to build a rectangular corral in a canyon. They have 200 feet of fencing to use for three sides of the rectangle (the canyon wall is used for the 4th side). a) What is the maximum area that they can fence in? b) What are the dimensions of the rectangle?

science
A 3.70 L sample of neon at 11.24 atm is added to a 10.0 L cylinder that contains argon. If the pressure in the cylinder is 5.24 atm after the neon is added, what was the original pressure (in atm) of argon in the cylinder?

Math
For the most recent year available, the mean annual cost to attend a private university in the United States was \$20,082. Assume the distribution of annual costs follows the normal probability distribution and the standard deviation is \$4,500. Ninety-five percent of all ...

math
a fish tank that holds 80 gallons of water is 55 percent full how many gallons are in the tank now and how many more gallons are needed to fill the tank

Physics
12

clemson
A farmer wants to make three identical rectangular enclosures along a straight river, as in the diagram shown below. If he has 1680 yards of fence, and if the sides along the river need no fence, what should be the dimensions of each enclosure if the total area is to be ...

Math
A movie poster shows King Kong towering over an adult human. On the poster, King Kong measures 42cm, while the human measures 5 cm. How tall is King Kong supposed to be, to the nearest foot?

math
there are 32 boys and 24 girls. what re the various number of teams that can be made that would have the same number of boys and girls on each team?

physics
when the students place the unknown cart on the scale the scale reads the mass of 1.20 kg a)calculate the percent difference b) state the reason for the difference . explain

Math
Please check my answers I think they are right if not please tell me where I went wrong. Thanks The annual net income of general electric for the period 2007-2011 could be approximated by P(t) = 3t^2- 24t +59 billion dollars (2<t<6) where t is time in years. a) compute p...

AC DC Circuit fundamentals
If a 10k ohm and a 5k ohm resister are connected in series across a 12 volt source whats the voltage across the 10k ohm resistor and 5 ohm resistor?

Physics
A motor of a certain elevator gives it a constant upward acceleration of 0.767 m/s2, the elevator starts from rest, accelerates for 2s, then continues with a constant speed. a) What is his final speed after 2s? b) Calculate speed after 1 ,and 3 s.? c) How far has it risen 1,2,...

math
if total ticket sales were \$1625 adult tickets were \$7.00 and student tickets were \$3.00 and twice as many students bought tickets than adults, how many students and adult tickets were sold?

chemistry
A solution is prepared by placing 23.9 g of KCl in a 0.500 L volumetric flask and adding water to dissolve the solid, then filling the flask to the mark. What is the molarity of an AgNO3 solution if 27.9 mL of the KCl solution react exactly with 45.0 mL of the AgNO3 solution?

Fiancne
Stephenson Real Estate Company was founded 25 years ago by the current CEO, Robert Stephenson. The company purchases real estate, including land and buildings, and rents the property to tenants. The company has shown a profit every year for the past 18 years, and the ...

Physics
A lorry of mass 12,000kg traveling at a velocity of 15 m/s crashes into the back of a moving car of mass 1500kg, traveling at a velocity of 5 m/s. The vehicles move together after the impact. Calculate their velocity.

math
jocelyn got 19 correct answers out of 25 questions on her last test. What percent of the questions did she answer correctly?

Chemistry
What is the total ionic equation of this: 3CaCl2(aq) + 2K3PO4(aq) → Ca3(PO4)2(s) + 6KCl(aq) Shw all physical states of the reactants and products

Physics
4. A ball is kicked toward a fence from a point 32 meters away. The velocity of the ball as it leaves the kicker’s foot is 24 m/s at an angle of 37 degrees above the horizontal. The top of the fence is 2.0 meters high. Assuming air resistance to be negligible…(1 ...

Maths
I don't know so help me

Grammar
Sentence: I tried all of the natural remedies, such as dishwashing liquid, but the ants kept coming back. Is there a comma before "such as"

MATH
Estimate the indicated derivative by any method y=1-x^2 ; estimate dy/dx , x=-1 I know I would use the f(x)= f(x+H)-(x)/h I am a bit overwhelmed with what to do next. Thanks John

algebra
I invest a sum of money at 10% annual simple rate and twice that amount at 12% annual simple interest.My total yearly in come from both investment was \$2890,how much was invested at each rate? Also What is the speed of each train if one train travels 8 mph faster than the ...

English
What are all of the prepositional phrases in the following sentence: Ancestors, in every variety of dress, from the Elizabethian knight to the buck of the Regency, stared down and daunted us.

algebra
Thank You

algebra
a 25 inch piece of a steel rod is cut into 3 pieces so that the length of the second piece is twice the length of the first piece.The third piece is 1 inch longer than 5 times the length of the first piece.What are the lengths of the pieces

physics
A soccer ball is kicked horizontally from the edge of a 125 m high cliff with an initial speed of 15 m/s. At what horizontal distance does the ball land?

physics
A ball is thrown straight up into the air. At each of the following instants, is the magnitude of the ball's acceleration greater than g, equal to g, less than g, or zero? Air resistance may be neglected. A) just after leaving your hand? B) at the very top (maximum height...

Chemistry (Ionic Equilibria)
When a WEAK acid can be said to be weak, and when a WEAK acid can be said to be strong? I only know the difference between weak acids and strong acids, but i don't know that even weak acids can be classified as weak and strong. Plz help

Math
What is the largest possible value of the sum of 1000

Physics 12
A sports car is travelling along a highway at a constant velocity of 36 m/s [N] exceeding the speed limit. It passes an unmarked police car parked on the shoulder of the highway. The police car accelerates from rest, 3.0 s after the sports car passed it, at the rate of 6.0 m/...

Calculus
Calculate the average rate of change of the given function f over the intervals [a, a+h] where h=1, 0.1, 0.01, 0.001, and 0.0001. I have no clue how to do this. Any help would be appreciated. Thanks I know I use the formula f=f (a+h) - f (a)/h Then do I need to plug in the -2x...

trig
A planes actual resulting ground speed and direction are 550 mph and N26E. A wind is blowing from the northeast. If the pilot is holding a course of N27E how fast is the wind blowing I'm just stumped. It's an extra credit question is basically why I'm stumped.

Trig
A planes actual resulting ground speed and direction are 550 mph and N26E. A wind is blowing from the northeast. If the pilot is holding a course of N27E how fast is the wind blowing?

Sublette
An appellate court that hears an appeal on a money laundering case from a district court

can yiu help me with this asignment

chemistry
The ionic radii of Na+ (atomic weight 22.99) and Cl- (atomic weight 35.45) are 1.0 and 1.8 Angstrom, respectively. Treating the ions as hard spheres, calculate the density of NaCl. Compare this with the measured density of 2.17 g/cm3.

science
(1.b) Calculate your de Bröglie wavelength and momentum when you are driving a car at a speed of 104 km/hr (~65 mph), assuming your mass is 80 kg.

maths
An ant must walk from one vertex of a cube to the "opposite" vertex (that is, the vertex that is farthest from the starting vertex) and back again to its starting position. It may only walk along the edges of the cube. For the entire trip its path must traverse ...

math
Every marble in a jar has either a dot, a stripe or both. The ratio of striped marbles to non-striped marbles is 3:1, and the ratio of dotted marbles to non-dotted marbles is 2:3. If six marbles have both a dot and a stripe, how many marbles are there all together?

Math
14.4ft.

algebra
Solve F(x) for the given domain. Include all of your work in your final answer. Submit your solution. F(x) = x2 + 2 F(x + h) =

algebra
12

physics
Assume a projectile is launched from ground height over a flat plane, at an angle of 50 degrees above the horizontal with an initial speed of 100 m/s. What is the initial velocity of the projectile parallel to the ground (in the x direction) and perpendicular to the ground (in...

American History
The Whiskey Rebellion A. caused the formation of the Democratic Societies. B. unified northern merchants and southern farmers. C. led to the development of two distinct political groups. D. created a single party political system. C?

English
The military because they give up their lives to fight for us.

Physics
Two ping-pong balls each have a mass of (1.4x10^0) g and carry a net charge of (3.99x10^0) μC. One ball is held fixed. At what height should the second ball be placed directly above the fixed ball if it is to remain there?