# Eric

Most popular questions and responses by Eric-
## Physics

A rocket-powered hockey puck moves on a horizontal frictionless table. The figure below shows the graphs of vx and vy, the x- and y-components of the puck’s velocity. The puck starts at the origin. The graph of the X-velocity is v=8t cm/s and the

*asked on September 11, 2015* -
## Math

Which of the images above represents a proof of the Pythagorean Theorem? Explain your choice, and then explain how the figure proves the Pythagorean Theorem.

*asked on November 19, 2012* -
## science

Which of the following gases was most likely present in Earth's earliest atmosphere? a. nitrogen b.hydrogen c.argon d.oxygen Help me please!

*asked on September 13, 2018* -
## Physics-Trajectory

A particle's trajectory is described by x =(12t3−2t2)m and y =(12t2−2t)m, where t is in s. What is the particle's speed at t=0s ? What is the particle's speed at t=5.0s ? Express your answer using two significant figures. What is the particle's

*asked on September 11, 2015* -
## chemistry

A 141-mg sample was placed on a watch glass that weighed 9.203 g. What is the weight of the watch glass and sample in grams?

*asked on January 31, 2012* -
## Math

The 3rd and 7th terms of an A.P are -1 and 11 respectively. Fine the nth term and the numbers of which must be added to get a sum of 430

*asked on September 20, 2017* -
## chemistry

Assuming equal concentrations, rank these aqueous solutions by their freezing point.? K2CO3, Li3PO4, Sn(ClO3)4, NH4I I tried to rank them according to the number of ions but i can't get it. highest freezing point --> lowest freezing point Sn(ClO3)4 ->

*asked on February 19, 2012* -
## physics

A firefighter a distance d from a burning building directs a stream of water from a fire hose at angle θi above the horizontal as in the figure. If the initial speed of the stream is vi, at what height h does the water strike the building? (Use theta for

*asked on February 18, 2011* -
## Chem HELP!!

Which one of the following sets of quantum numbers can correctly represent a 3p orbital? a) (n = 3 l = 1, ml = 2) b)(n = 1, l = 3, ml = 3) c) (n = 3, l = 2, ml = 1) d) (n = 3, l = 1, ml = -1) e) (n = 3, l = 0, ml = 1)

*asked on October 5, 2014* -
## physics

a 65kg person dives into the water from the 10m platform. she comes to a stop 2m below the surface of the water. what net force did the water exert on the swimmer? so for the net force i got -2548N i know: vf^2=vi^2 + 2ad vf^2 = 0 + 2(9.8)(10) vf^2 = 196

*asked on February 6, 2014* -
## physics

A projectile is fired in such a way that its horizontal range is equal to 8.5 times its maximum height. What is the angle of projection?

*asked on February 18, 2011* -
## Physics

A massive steel cable drags a 20kg block across a horizontal, frictionless surface. A 100N force applied to the cable causes the block to reach a speed of 4.2m/s in a distance of 2.1m . What is the mass of the cable?

*asked on May 30, 2015* -
## Chemistry

When carbon is burned in air, it reacts with oxygen to form carbon dioxide. When 26.4 g of carbon were burned in the presence of 82.1 g of oxygen, 11.7 g of oxygen remained unreacted. What mass of carbon dioxide was produced? Express your answer to one

*asked on September 14, 2016* -
## Spanish

Are these correct? I. Rewrite each sentence by replacing the direct object in quotation marks with a direct object pronoun [me, te, lo, la, nos, los, las]. Ejemplo: No conozco "al jefe del departamento." --> No lo conozco. 1. Esa compañía vende "casas

*asked on January 23, 2014* -
## physics

The same amount of heat entering identical masses of different substances produces different temperature changes. Calculate the final temperature when 1.25 kcal of heat enters 1.25 kg of the following, originally at 20.0°C. (a) water (b) concrete (c)

*asked on July 19, 2013* -
## Introduction to computers

Which Microsoft operating system started the process of authenticating users with a username and password

*asked on November 10, 2015* -
## ChemII

A saline solution is 0.9% NaCl. What masses of NaCl and water would be required to prepare 50. L of this saline solution? Assume that the density of water is 1.000g/mL and that the NaCl does not add to the volume of the solution.

*asked on January 9, 2011* -
## Math

Paul is painting a square wall with an area of 115 square feet. To the nearest foot, what is the length of the wall? Hint: A = s2. 11 29 42 58

*asked on November 19, 2012* -
## chemistry

A crystalline material containing 30 grams of barium chloride crystals was placed into an oven at 400 degrees c and heated for two hours. It was then cooled and weighed. the new mass was less than before it was heated, containing 20 grams if barium

*asked on January 27, 2011* -
## Physics

A ball of mass m makes a head-on elastic collision with a second ball (at rest) and rebounds with a speed equal to one-fourth its original speed. What is the mass of the second ball?

*asked on December 10, 2009* -
## Educational Technology and Online Learning

what is the purpose of the introduction in an expository essay

*asked on September 14, 2016* -
## physics

Rubbing your hands together warms them by converting work into thermal energy. If a woman rubs her hands back and forth for a total of 12 rubs a distance of 7.50 cm each and with a frictional force averaging 30.0 N, what is the temperature increase? The

*asked on July 19, 2013* -
## physics 11

A swimmer swims perpendicular to the bank of a 20.0 m wide river at a velocity of 1.3 m/s. Suppose the river has a current of 2.7 m/s [W]. (a) How long does it take the swimmer to reach the other shore? (b) How far downstream does the swimmer land from his

*asked on October 20, 2015* -
## Math

Simplify (Log75+log9+log5)÷(log5+log45)

*asked on November 10, 2016* -
## physics

In a local bar, a customer slides an empty beer mug down the counter for a refill. The bartender is momentarily distracted and does not see the mug, which slides off the counter and strikes the floor at distance d from the base of the counter. The height

*asked on February 18, 2011* -
## Physics

When a 65 kg person climbs into a 1000 kg car, the car's springs compress vertically by 3.1 cm. What will be the frequency of vibration when the car hits a bump? Ignore damping.

*asked on January 27, 2010* -
## statistics

Scores on the GRE (Graduate Record Examination) are normally distributed with a mean of 541 and a standard deviation of 101. Use the 68-95-99.7 Rule to find the percentage of people taking the test who score between 238 and 844 The percentage of

*asked on December 8, 2016* -
## Chemistry

The vapor pressure, P, of a certain liquid was measured at two temperatures, T. Represented in a table: T (in Kelvin) ------- P(in kPa) [325] --------------- [4.00] [775] --------------- [8.59] What is the enthalpy of vaporization for this liquid? (Delta H

*asked on January 23, 2012* -
## chemistry help~Please!!!

What are the Ka and/or Kb value for 1M ZnCl2 Show work please!!!

*asked on April 11, 2014* -
## Math

The population of town A increases from 1,346 to 1,500. In the same period, the population of town B increases from 1,546 to 1,800. a. Find the percent of increase in population for town A and for town B. b. Which town had the greater percent of increase?

*asked on December 13, 2012* -
## physics

The engine of a large ship does 2.05 multiplied by 108 J of work with an efficiency of 4.00%. (a) How much waste heat (J) is produced? (b) How many barrels of fuel are consumed, if each barrel produces 6.00 multiplied by 109 J of heat when burned?

*asked on July 24, 2013* -
## math, economics, game theory

Two people have 10 dollars to divide between themselves. they use the following procedure. each person names a number of dollars (nonnegative integer), at most equal to 10. IF the sum of the amounts that the people name exceeds 10 and the amounts named are

*asked on September 10, 2007* -
## Math

Thinking about the different types of numbers you learned in this unit, how would you help someone remember the differences between rational and irrational numbers? Remember to mention some of the Key Words from your lessons

*asked on November 19, 2012* -
## Math

Ann, Mara, Jenny, Tina, and Sue are sisters. Two of the five sisters must help their father at this business each Saturday. How many combinations of two sisters are possible?

*asked on September 13, 2011* -
## physics

In 1986 a gargantuan iceberg broke away from the Ross Ice Shelf in Antarctica. It was approximately a rectangle 160 km long, 45.0 km wide, and 250 m thick. (a) What is the mass of this iceberg, given that the density of ice is 917 kg/m3? (b) How much heat

*asked on July 20, 2013* -
## physics

A magician pulls a tablecloth from under a 200 g mug located 30.0 cm from the edge of the cloth. The cloth exerts a friction force of 0.105 N on the mug, and the cloth is pulled with a constant acceleration of 3.50 m/s2. How far does the mug move relative

*asked on February 24, 2011* -
## physics

(a) A rectangular gasoline tank can hold 41.0 kg of gasoline when full. What is the depth(m) of the tank if it is 0.400 m wide by 0.900 m long? (b) What is the volume(gal) of the tank? (It is suitable for a passenger car.)

*asked on July 22, 2013* -
## physics

The "steam" above a freshly made cup of instant coffee is really water vapor droplets condensing after evaporating from the hot coffee. What is the final temperature of 280 g of hot coffee initially at 90.0°C if 2.50 g evaporates from it? The coffee is in

*asked on July 21, 2013* -
## Chemistry

A solution is made by dissolving 0.500 mol of HF in enough water to make 1.00 L of solution. At 21 C, the osmotic pressure of the solution is 1.35 atm. What is the percent ionization of this acid? This is what i did.. is it correct? (1.35 atm) =

*asked on February 19, 2012* -
## physics

A fireworks rocket explodes at height h, the peak of its vertical trajectory. It throws out burning fragments in all directions, but all at the same speed v. Pellets of solidified metal fall to the ground without air resistance. Find the smallest angle

*asked on February 18, 2011* -
## physics

A certain heat engine does 8.0 kJ of work and dissipates 8.00 kJ of waste heat in a cyclical process. (a) What was the heat input to this engine? (b) What was its efficiency?

*asked on July 24, 2013* -
## Organic Chem

A 20 g mixture containing 95% (by weight) of A and 5% of B is recrystallized in toluene (b.p. 110 C). Solubility for compound A is 1.5 g @20 degrees and 10 g @ 110 degrees. For compound B solubility is 0.5 g @20 degrees and 8 g @ 110 degrees. What amount

*asked on October 5, 2010* -
## physics

A hand-driven tire pump has a 2.50 cm diameter piston and a maximum stroke of 31.0 cm. (a) How much work (J) do you do in one stroke if the average gauge pressure is 2.40 multiplied by 105 N/m2 (about 35 psi)? (You may consider this an isothermal process.)

*asked on July 24, 2013* -
## chemistry

a certain radioactive nuclide has a half life of 5.00 hour. Calcuate the decay rate for 1.000 mole of this nuclide __________ decay s-1

*asked on July 12, 2012* -
## math

Mrs. Bollo's second grade class of thirty students conducted a pet ownership survey. Results of the survey indicate that 8 students own a cat, 15 students own a dog, and 5 students own both a cat and a dog. How many of the students surveyed own no cats?

*asked on November 28, 2010* -
## science

How do you calculate how long will it take an object dropped from a window to fall a distance of 78.4 meters?

*asked on October 17, 2011* -
## college physics

A(n) 13,300 lb railroad car traveling at 7.4 ft/s couples with a stationary car of 6790 lb. The acceleration of gravity is 32 ft/s^2. What is their velocity after the collision (ft/s)? And what impulse did the first car receive? Answer in units of lbs. Any

*asked on March 23, 2010* -
## Introduction to computers

You call the help desk to report a problem you are having on your computer. The technician asks you what operation system you are running. You know it is windows 7 but you forgot which version . How can you find out.

*asked on November 10, 2015* -
## Math

What is the sqaure root of thirty six over forty nine?

*asked on November 19, 2012* -
## Spanish

Are these correct? Thank you for helping Finish the following sentences including at least one possessive adjective (mi[s], tu[s], su[s], nuestro[s] or nuestra[s]) in your answer. Ejemplo: La profesora que tiene mi amiga es antipática, pero "mis

*asked on January 24, 2014* -
## Physics

Three positive point charges are located at the corners of a rectangle. Find the electric field at the fourth corner if q1 = 5 nC, q2 = 6 nC, and q3 = 7 nC. The distances are d1 = 0.6 m and d2 = 0.2 m. (Let the positive x-direction be to the right, and the

*asked on January 18, 2016* -
## PHYSICS

TRACY SWIMS ACROSS A STREAM OF WIDTH 40.0M IN 33.0S WHEN THERE IS NO CURRENT.SHE TAKES 59.0 TO COVER THE SAME DISTANCE WHEN THERE IS CURRENT.FIND THE SPEED OF THE CURRENT RIVER.

*asked on November 19, 2007* -
## french

how do you conjugate aimer mieux? do you just conjugate the aimer part?

*asked on February 9, 2008* -
## Spanish

Are these correct? Answer the following questions using the present progressive. Be sure to answer with the same verb that is used in each question. 1. Creo que Xavier (1) _____ (2) __________ en la casa de sus padres mientras asiste a la Universidad.

*asked on January 29, 2014* -
## physics

About 50,000 years ago, in an area located outside Flagstaff, Arizona, a giant 4.5x10^7 kg meteor fell and struck Earth, leaving a 180 m hole now known as Barrington crater. If the meteor was traveling 20000 m/s upon impact, with what average force did the

*asked on March 3, 2011* -
## Physics

One kind of slingshot consists of a pocket that holds a pebble and is whirled on a circle of radius r. The pebble is released from the circle at the angle θ so that it will hit the target. The angle in the drawing is 35.5°. The distance to the target

*asked on September 28, 2012* -
## Chemistry

The specific heat of a certain type of metal is 0.128 J/(g-c). What is the final temperature if 305 J of heat is added to 86.9 g of this metal initially at 20 degrees C? Tfinal = ___ C

*asked on February 8, 2012* -
## accouting

Nancy Company has budgeted sales of $300,000 with the following budgeted costs: Direct materials $60,000 Direct manufacturing labor 40,000 Factory overhead Variable 30,000 Fixed 50,000 Selling and administrative expenses Variable 20,000 Fixed 30,000

*asked on April 2, 2011* -
## Economics

1. An economy's production possibilities frontier is also its consumption possibilities frontier. a. under all circumstances b. under no circumstances c. when the economy is self-sufficient d. when the rate of tradeoff between the two goods being produced

*asked on September 9, 2012* -
## chemistry

E degrees (V) A galvanic cell based on the following half reaction s Au3+ 3e- ----> Au 1.50 Mg2+ 2e- ------> Mg -2.37 The cell is set up at 25 C with [Mg2+] = 1.00 x 10^-5 M The cell potential is observed to be 4.01 V. Calculate the [Au3+] that must be

*asked on July 13, 2012* -
## Physics

A soft drink can contains about 0.20 kg of liquid at 5 oC. Drinking this liquid can actually consume some of the fat in the body, since energy is needed to warm the water to body temperature (37 oC). How many kcal should the drink have so that it is in

*asked on September 20, 2010* -
## Physics

two skaters, each of mass 55 kg, approach each other along parallel paths separated by 3.8 m. They have opposite velocities of 1.9 m/s each. One skater carries one end of a long pole with negligible mass, and the second skater grabs the other end of it as

*asked on June 2, 2012* -
## Algebra

Gymnast Clothing manufactures expensive soccer cleats for sale to college bookstores in runs of up to 500. Its cost (in dollars) for a run of x pairs of cleats is C(x) = 3000 + 9x + 0.1x2 (0 ≤ x ≤ 500). Gymnast Clothing sells the cleats at $130 per

*asked on February 19, 2012* -
## Physics

Three forces are exerted on an object placed on a tilted floor. Forces are vectors. The three forces are directed as shown in the figure. If the forces have magnitudes F1 = 2.0 N, F2 = 17.0 N and F3 = 15.0 N, where N is the standard unit of force, what is

*asked on September 11, 2015* -
## physics

one ball is dropped off a cliff. A second ball is thrown down 1 second later with an initial speen of 40 ft/sec. How long after the second ball is thrown will the second ball overtake the first?.

*asked on May 11, 2011* -
## Chemistry

Using the equation: 2C2H6 + 7O2--> 4CO2 + 6H20 How many moles of CO2 are produced by the reaction of 21.0 mol O2? Again, not sure how to write it correctly, but if I multiply 7O2 by 3, then I should do the same to the other side of the equation to make it

*asked on February 19, 2016* -
## PE

How does esteem affect the way you behave?

*asked on October 4, 2016* -
## physics

One side of the roof of a building slopes up at 35.5°. A student throws a Frisbee onto the roof. It strikes with a speed of 15.0 m/s and does not bounce, but slides straight up the incline. The coefficient of kinetic friction between the plastic and the

*asked on February 24, 2011* -
## Calculus

The cost, in dollars, to produce q units is C(q)=8050+15q What is the fixed cost?

*asked on July 24, 2019* -
## Calculus

Find the value(s) of c guaranteed by the Mean Value Theorem for Integrals for the function over the given interval. f(x) = 4√x [4, 9]

*asked on November 15, 2016* -
## english

what does miss rosie symbolize in the poem miss rosie by lucille clifton?

*asked on May 18, 2010* -
## Chemistry

You have a 22L cylinder of helium at a pressure of 150atm and a temperature of 31C. How many ballons can you fill, each with a volume of 5.0L, on a day when the atmospheric pressure is 755mmHg and the temperature is 22C?

*asked on September 27, 2009* -
## Physics

The components of vector A⃗ are Ax = + 3.90 and Ay = -4.00. What is the angle measured counterclockwise from the +x-axis to vector A⃗ ?

*asked on September 11, 2015* -
## math

A company made $4 million in the second quarter. This is 1/3 more than it made in the first quarter and 4/5 of what it made in the third quarter. How much did the company make in the three quarters combined?

*asked on September 19, 2011* -
## College Physics

A concept question: Suppose that the centripetal force acting on an object in circular motion were increased to a new value, and the object remained in circular path with the same radius. How would its motion be affected?

*asked on September 30, 2010* -
## Chemistry

You have a 22L cylinder of helium at a pressure of 150atm and a temperature of 31C. How many ballons can you fill, each with a volume of 5.0L, on a day when the atmospheric pressure is 755mmHg and the temperature is 22C? I know I use PV=nRT, but what

*asked on September 27, 2009* -
## Economics

The well known nationally syndicated columnist David Broder reported the recent findings of two academic political scientists. These scholars found that voters are quite turned off by negative campaigns of politicians. Many people went as far as not voting

*asked on July 15, 2013* -
## Chemistry

How many calories are required at 0 degrees C to melt an ice cube with a mass of 25g? I got 2000 cal. Could you tell me if this is right?

*asked on September 18, 2010* -
## college

Two point charges have a total charge of 505 µC. When placed 1.10 m apart, the force each exerts on the other is 19.3 N and is repulsive. What is the charge on each? (Round your answers to the nearest µC.)

*asked on August 29, 2010* -
## Physics

A circus cat has been trained to leap off a 12-m-high platform and land on a pillow. The cat leaps off at v0 = 3.6 m/s and an angle θ = 37°

*asked on February 6, 2017* -
## Economics

Thomas Schelling, an expert on nuclear strategy and arms control, observed in his book The Strategy of Conflict (Cambridge, MA: Harvard University Press, 1960), "The power to constrain an adversary depends upon the power to bind oneself." Explain this

*asked on July 15, 2013* -
## statistics

Suppose 1,600 of 2,000 registered voters sampled said they planned to vote for the Independent candidate for president. Using the 0.95 degree of confidence, what is the interval estimate for the population proportion (to the nearest tenth of a percent)?

*asked on February 2, 2013* -
## Math

A class has 27 students. Fifteen are boys and the rest are girls. What is the ratio of girls to total students? 12 : 15 15 : 12 27 : 12 12 : 27

*asked on November 20, 2012* -
## math

in which stem do most of the data fall 1 ,2 3, or 4

*asked on October 6, 2016* -
## Chemistry

A 50.0-mL sample of 0.10 M HNO2 is titrated with 0.10 M NaOH. What is the pH after 25.0 mL of NaOH have been added?

*asked on December 7, 2010* -
## english

chick: a young woman A. direct definition B. indirect definition a

*asked on February 18, 2012* -
## chemistry

How much faster will neon effuse than krypton, given that the molar mass of krypton is 83.8 grams and that of neon is 20.18 grams?

*asked on July 14, 2013* -
## physics

A basketball star covers 2.70 m horizontally in a jump to dunk the ball (see figure). His motion through space can be modeled as that of a particle at a point called his center of mass (which we shall define in Chapter 9). His center of mass is at

*asked on February 18, 2011* -
## Math

Martin used some apples to make muffins.Omar used 5 fewer than half as many apples as Martin used

*asked on March 12, 2019* -
## physics

An ice bag containing 0°C ice is much more effective in absorbing heat than one containing the same amount of 0°C water. (a) How much heat in kcal is required to raise the temperature of 0.700 kg of water from 0°C to 27.0°C? (b) How much heat is

*asked on July 19, 2013* -
## Algebra 2

Create an explicit equation for each recursively defined sequence below a1=17,an+1=an-7

*asked on October 13, 2015* -
## Algebra

Tell whether the lines for each pair of equations are parallel perpendicular of neither y=-3x+7 -2x+6y=3 Tell whether the lines for each pair of equations are parallel perpendicular of neither y=(-1/5)x=6 -2x+10y=5

*asked on January 18, 2016* -
## math

A 10 kg quantity of a radioactive isotope decays to 3 kg after 17 years. Find the decay constant of the isotope.

*asked on February 3, 2011* -
## math

A 10 kg quantity of a radioactive isotope decays to 3 kg after 17 years. Find the decay constant of the isotope.

*asked on February 3, 2011* -
## physics

A 1.80 m radius playground merry-go-round has a mass of 120 kg and is rotating with an angular velocity of 0.300 rev/s. What is its angular velocity after a 19.0 kg child gets onto it by grabbing its outer edge? The child is initially at rest.

*asked on July 18, 2013* -
## history

Hamilton / Jefferson Readings Quiz 1. Alexander Hamilton thought that having a virtuous citizenry was a necessity in a Repulic. A) True B) False 2. Who said "The goodness of a government consists in a vigorous execution?" A) Thomas Jefferson B) Alexander

*asked on May 1, 2012* -
## Math

Nell made a pizza. she cut the pizza into fourths. then she cut each fourth. nell and her friens ate 6 of the smaller pieces of the pizza. What fraction of the pizza did Nell and her friends eat? What fraction of the pizza did Nell and friends Not eat?

*asked on December 4, 2014* -
## Calc

Find the critical numbers of the functions. f(0) = 2sec0 +tan0 on the interval [0,2pi]

*asked on November 15, 2016* -
## physics

In 1986 a gargantuan iceberg broke away from the Ross Ice Shelf in Antarctica. It was approximately a rectangle 160 km long, 45.0 km wide, and 250 m thick. (a) What is the mass of this iceberg, given that the density of ice is 917 kg/m3? (b) How much heat

*asked on July 21, 2013* -
## science

an electric heater draws 5A of current from the 120-V power line. How much will it cost to run this heater for one day if the cost of energy is 10 cents

*asked on September 4, 2019*