# Robert

Newest questions posted by Robert-
## Science

A proton accelerates from rest to 3.00x10^6m/s in 1.00x10^-6s in a uniform electric field E. What is the magnitude of the electric field? -
## Physics

A cube made ouk and side 15cm floats in water with 10.5cm of it's depth below the surfaces and with it's side's vertical what is density of oak -
## Physics

A block cedar has a mass of 200 kg and density of 570 what fraction of the wood will be surface of block is floating in water -
## Physics

A space vehicle travelling at a velocity of 6000km/h separates into two parts of mass 1200 kg and 300 kg. The two parts continue moving in the same direction with the lighter section moving at 6200km/h. Making use of the principle of conservation of -
## Physics

A racing car of mass 850 kg accelerates from 20 km/h to 160 km/h over a distance of 300 metres. Frictional forces and wind resistance can be assumed to be 800N. Determine the following: (i)The average acceleration (ii)The time taken to accelerate from 20 -
## Calculus

How do you take the limit of a composite piecewise function f(f(x))? Only the graph is given. lim f(f(x)) x->2 I figured the way to do it was to find the lim f(x) = C then find lim f(x). x->2 x-> C The simple questions on Khan academy's "Limits of -
## Math

A helicopter drops a box of supplies after a disaster. The function represents the height y (in feet) of the box t seconds after it is dropped. After how many seconds does the box hit the ground? y=100-16t^2 -
## Physics

The velocity of sound in air is about 330m/s, and in water is about 1700m/s. Calculate the critical angle for sound leaving air and entering water. -
## Physics 2

A fisherman notices that his boat is moving up and down periodically rowing to waves on the surface of the water. It takes 3.0 seconds for the boat to travel from its highest point to it's lowest, a total distance of 0.800m. The fisherman sees that the -
## Physics

An observer is located directly between two speakers, located 20m apart. The speakers are in phase with each other, and both are emitting a sound with a frequency of 60Hz. How far away from the centre should the observer move to get the first destructive -
## Physics

Sapose active sonar on a stationary ship is used to determine the speed of a ship that is moving away from it. A sonar ping is emitted at a frequency of 1400Hz, and the echo returns with a frequency of 1390Hz.The speed of sound in sea water is -
## physics

Calculate the speed of a satellite moving in a stable circular orbit about the Earth at a height of 3.004km. -
## physics

During an Apollo lunar landing mission, the command module continued to orbit the Moon at an altitude of about 58.6 km. How long did it take to go around the Moon once, in seconds? -
## Math

Matter is in a liquid state when its temperature is between its melting point and its boiling point. Suppose that some substance has a melting point of negative 46.81 degrees and a boiling point of 357.63 degrees . What is the range of temperatures in -
## Math

An architect make a model of a building with a volume of 1440 cubic centimeters? The length of the model is 15 centimeters and the width is 12 centimeters. How many centimeters tall is the model -
## combining like terms

The length of a rectangle is 4.5 units longer than the width,w. Find the perimeter of the rectangle -
## Math

measure of angle A and measure of angle B are complementary. measure of angle A = 3x + 12 and measure of angle B = 2x - 22. Find the measure of each angle. -
## Math

-6 greater equal to 13 + 5 which of these values of X makes the inequality true -3.9 -1.2 3/13 -7/15 Please help explain answer -
## Math

-6 greater equal to 13 + 5 which of these values of X makes the inequality true -
## Real Estate

What number less 6% equals 610,000 -
## History

What inventions were made because of the telegraph? -
## Social studies

I need help with lesson 12 unit 2 for seventh grade there is a unit test called Eastern Europe and Russia and unit test 7. Many words offer clues to media bias. Which word below would mostly likely signal bias. A. Was B. Did C. Should D. Might -
## Organic Chemistry

Procedure: 1) Accurately weigh approximately 0.40 g of Dimethyl maleate into a 50 mL round bottom flask that possesses a ground glass joint, and record the weight. 2) Dissolve the Dimethyl maleate in 10 mL of methanol, and add approximately 5 drops of -
## Organic Chemistry

Procedure: 1) Accurately weigh approximately 0.40 g of Dimethyl maleate into a 50 mL round bottom flask that possesses a ground glass joint, and record the weight. 2) Dissolve the Dimethyl maleate in 10 mL of methanol, and add approximately 5 drops of 10% -
## math

A third staircase in a swimming pool has a landing of 18 inches and a vertical rise of 12 inches per step. To the nearest degree, calculate the following measures. a) What is the angle of elevation rounded to the nearest whole degree? b) If the elevation -
## Math

Find the vertex focus directrix and axis of symmetry of each parabola y²–8x–6y–3=0 -
## calculus

Elasticity a) Find the elasticity of the demand function q + 2p = 5000 when p = $1000, and q = 3000. b) How would revenue be affected by a price increase? -
## physics

200g of steam at 110°C is condensed, and the resulting water is frozen into ice at 0°C. How much heat was removed? -
## Chemistry

A fixed amount of oxygen gas is held in a .500 L tank at a pressure of 4.09 atm. The tank is connected to an empty 1.50 L tank by a tube with a valve. After this valve has been opened and the oxygen is allowed to flow freely between the two tanks at a -
## ap

What is the most accurate description of human nature? -
## History

How does Galileo defend himself against these charges of heresy by the Inquisition? -
## Statistics

Q1:(a) Make a relative frequency table of the data. Enter your answers to three decimal places. Cell Phone Owned Relative Frequency Android smartphone iPhone smartphone Blackberry smartphone Cell phone not smartphone No cell phone Total (b) Round your -
## pre calc

The number N of bacteria in a culture at time t (in hours) grows exponentially according to the function N(t) = 1000e^0.01t When will the number of bacteria reach 1700? I though you would do 1700=1,000^e0.01t and solve for t but i keep getting the wrong -
## pre calc

The population of a colony of mosquitoes grows exponentially according to the function P(t) = P0ekt 1. If there are 1,000 mosquitoes initially and there are 1800 after 1 day, what is the size of the colony after 3 days? 2. How long will it take the colony -
## computer programming

Design the logic for a program that allows a user to enter any amount of numbers up to 10 or until a sentinal value of -1 is entered. Then the program displays the count of the numbers entered and numeric average of the numbers (not including the -1 of -
## DISTANCE TIME AND SPEED

if the speed of a car is increased from 90km/h to 120km/h, the time is reduced by one hour to reach the destination. Calculate the distance between the two towns. -
## Physics

Huck Finn walks at a speed of 0.60 m/s across his raft (that is, he walks perpendicular to the raft’s motion relative to the shore). The raft is traveling down the Mississippi River at a speed of 2.20 m/s relative to the river bank. What is Huck’s -
## Physics

A projectile is shot from the edge of a cliff 145m above ground level with an initial speed of 65.0 m/s at an angle of 37.0° with the horizontal. How far did the shot go horizontally? -
## Physics

Your gun is perfectly level with a monkey at a distance of 55 m. Your bullet is shot perfectly horizontal at a speed of v_0=38 m⁄s at the exact moment the monkey lets go of the branch. How far does the monkey fall before the bullet hits it? -
## Physics

During your trip in question 10, you encounter some construction. In 25 seconds, you have to slow from 70 mph to 55 mph. What is your acceleration in mph/s? -
## Physics

After today’s test, you are going to meet some friends at Disney World. The total distance to Disney World is 68 miles. If you make it there in 72 minutes, what is your average velocity in miles per hour? -
## Physics

Assume you have a canon aimed straight up. The cannonball is shot at a velocity of v_0=69 m/s. How high does the cannonball go? How much time does it take the cannonball to reach that height? -
## College Algebra

x+2y=0 x+3y+z=1 -4x-y-z=23 -
## math

i need ratios of 5/6 -
## Math

Roberto wants to reduce a drawing that's is 12 inches long by 9 inches wide.if his new drawing is 8 inches long. How wide will it be -
## Math

An 8.5 centimeter green bean pod contains peas that average 0.45 centimeter in diameter. How many peas are in the pod -
## Math

A chemist needs 22 liters of a 14% acid solution. He has a 10% solution and a 20% solution available to form the mixture. How much of each should be used to form the 14% solution? I'm having a really hard time forming an equation for this. I've -
## Chemistry

An element has three stable isotopes. One has a mass number of 63 and an abundance of 50%. The second has a mass number of 65 and an abundance of 30%. The third has a mass number of 67 and an abundance of 20%. Calculate the relative atomic mass of this -
## Biology

why is protein folding important to enzyme activity? -
## math

32 cans for 7 dollars how much per can -
## Linear Algebra

The Vector v has a length of 15 and points at an angle of 30 degrees. The Vector u has a length of 17 and points at an angle of 55 degrees. What is u*v? I know to get my answer I need to use this format |u|*|v|*cos(theta) however I am stuck at setting up -
## Math

Suppose that A and B are independent events such thatP(A)=.50 andP(B)=.30 . Find and P(A U B) and P(A upside down U B) . -
## Mayh

Bert gave me 1/2 of the candy bar then I gave 1/2 of what I have to my sister What fraction of the whole candy bar did my little sister get and what percent did she get -
## Communication for Business

Please could you help me with a good attention getter for a presentation on how interviews were done -
## Chemistry

If the heat of combustion for a specific compound is -1250.0 kJ/mol and its molar mass is 35.39 g/mol, how many grams of this compound must you burn to release 352.40 kJ of heat? -
## Math

Gina has 4 red ribbons, 6 times as many blue ribbons as green ribbons, and 1/4 as many green ribbons as red ribbons. How many ribbons does she have in all? -
## Physics

Two metallic spheres of mass .001 kg hang from a point by .3 m strings. Each is given the same amount and sign of charge. After equilibrium is reached, they each make an angle of 20 degrees relative to the vertical. Determine the amount of charge in each -
## math

how do you write twenty million three hundred thousand -
## physics

What is the mass which causes a spring of k = 100 N/m to stretch by 10 cm? -
## Math

What point on the unit circle corresponds to -5pi/4? A. (-Root2/2, Root2/2) B.(-Root3/2, 1/3 C.(-1/2, Root3/2) D.(0,1) D? -
## math

a boy runs 18.4 miles in 4.5 hours, how many miles can he run in 1 hour? -
## Finance

Your program has a research and development project scheduled to start in January 2014 which is expected to take 40 months to complete. The project is expected to cost a total of $150 million (then-year dollars), with cost expected to be incurred as -
## Math

The Japanese yen corresponds to the american dollar. If the exchange rate is 150 Yen for 1 Dollar, then A japanese car sold in america for $10,000 will bring in 1,500,000 yen. If the exchange rate changes to 120 yen for each dollar, then what price in -
## College algebra

Matt and Jena, working together, can clean the house in 9 hours. Working alone, Jena takes three times as long as Matt. How long does it take Matt to clean the house. -
## Grammar

When ending a letter to a high gov't official with the phrase 'Respectfully Submitted', are both words capitalized, or just the first? -
## AP Physics

A 5.86 kg block initially at rest is pulled to the right along a horizontal surface by a constant, horizontal force of 14.4 N. The coefficient of kinetic friction is 0.14. The acceleration of gravity is 9.8 m/s 2 . Find the speed of the block after it has -
## Math

jeff rode bike 5 times as many miles as Vin. together they rode 18 miles. how many miles did each boy ride -
## Cheistry

single titration was performed which required 11.82 ml of .1 M Na2S2O3 the density of the original undiluted bleach unknown was 1.04 g/ml calculate the number of moles of ClO- in the sample titrated ClO- + 2I- + 2H+ === I2 + Cl- + H20 I2 + 2S2O2/3- === 2I- -
## Life Skills

How Does Empathy Positively Affect Education? -
## Chemistry

Are my answers correct? Calculate the molarity: a) 0.500 mol of NaOH in 2.45 L of solution. b) 24.1 g of NaCl in 853 mL of solution. a: 0.2 M b: 0.49 M -
## Physical Science

If a skydiver has a forward velocity of 40 m/s, what is the forward velocity after one second? What is the downward velocity after one second? -
## math

I am between 20 and 30. When you put me into 5 equal groups, there is an odd number in each group and one is left over. what number am I? -
## Chem

Depending upon the tip of a dropper pipet, there are approximately 20 drops per milliliter of water. The experimental procedure indicates the addition of 5-10 drops of each solution to the test tubes. Calculate the volume range in milliliters for the -
## math

describe a real world relationship between the area of a rectangle and its width, as the width varies and the length stays the same. Sketch a graph to show this relationship. -
## chemistry

find the# of molecules in 5.3 moles of h20 -
## Math

If I work 5 days a week making $8.38 an hour, how would I figure out how much I make a month, getting paid bi weekly? -
## Physics

While John is traveling along a straight interstate highway, he notices that the mile marker reads 280. John travels until he reaches the 156-mile marker and then retraces his path to the 175-mile marker. What is John's resultant displacement from the -
## Matg

Juanita told her dad that she won 80% of the card games she played yesterday. If she won 4 games, how many games did she play? -
## Chemistry

Dividing 0.32g of sulfur by its density of 2.07g/cm^3 results in an answer with three significant figures? Am I right? -
## Geometry

Question: If a ray divides an angle into two supplementary angles, then the original angle is a straight angle. True? -
## Geometry

Line TV bisects -
## chemistry

A 30.0 g sample of water at 10.0°C is mixed with 50.0 g of water at 57.0°C in a calorimeter. Calculate the final temperature of the mixture -
## navarro college biology

During the sequencing of dna into a protein, what is the first step? -
## English

Please could you help me that I don't have run on sentences or if I need commas.After reading "Man's Nature is Good" Mencius argues that man is born good but, that life itself makes a man evil. He states "Human nature is inherently good, just like water -
## Algebra

Solve. -9(4-k)/12 = 9(k+1)/8 -
## Math

The vertical backboard located 4ft from the baseline supports the rim of the basketball net. The backboard measures 6ft wide by 4ft high. The shooter's square is a white box above the rim of the basket. It must measure 1 1/2 ft high and 2ft wide. What is -
## life orientation project

research and briefy discuss the following processes that the community must engage whenever there is an issue before and during a protest :how to engage in a protest, protest restrictions,permit to hold a protest, activities during a protest,as well as the -
## math

If A + B + c = 180 then show that sinA + sinB + sinC=4cosA/2. cosB/2 . cosC/2 -
## General Chemistry 132

When solid NH4NO3 is dissolved in water at 25celcius, the temp of the solution decreases. What is true about the signs of enthalpy and entropy for this process? I understand entropy is positive, however, i do no understand why enthalpy is also positive. -
## precalculus

hyperbola with vertices at (0,+/-2), and asymptotes y=+- 1/2x -
## Science

How does the sun's gravitational attraction to the earth compare to that of the moon? -
## math:Fundamental Counting Principlal

solve the problem by applying the fundamental counting principal with two groups of items. Shaun is joining a music club. as part of ther 4-cd introductory package she can choose from 12 rock, 10 alternative, 7 country, and 5 classical. if Shaun choose one -
## math

A baker can make a cupcake for $2.30. She would like a profit of 50 cents each. What is the percent markup on the cupcake, to the nearest tenth of a percent? -
## math

2 line segments intersect to form an angle that has a measure pf 50.7 degrees. What is the measure in degrees of an angle that is supplementary to this angle. I don't understand what this question is asking me. Can someone explain it to me? -
## Chemistry

Use half reaction to balance: CuS + NO3^- = Cu(NO3)2 + NO2 + SO2 S^2- = SO2 S Oxidized Cu^2+ + NO3^- = NO2 + Cu(NO3)2 N Red After balancing the atoms & balancing the charges, I cannot get all the correct coefficients -
## Physics

You're an investigator for the National Transportation Safety Board, examining a subway accident in which a train going at 80km/h collided with a slower train traveling in the same direction at 20km/h . Your job is to determine the relative speed of the -
## Math 7th grade

Geraldo bought some computer software on layaway. He paid $12 down and must make a payment of $5 each week for 4 weeks. How much will Geraldo pay in all? -
## Algebra 2

Multiplying or dividing rational expressions 6x^2 + 13x - 5 divide by 6x^2 -23x + 7 Need to show my work. -
## multivariable calculus

show that a=!0 , the equation p=2asin0cos0 describes the sphere centered(a,0,0) at radius|a| -
## math

i have tryed this like ten times but cant get the answer can u help. 58,00 times 7.40% after u get the answer between the two multiply by 3