Wednesday

February 22, 2017
Total # Posts: 409

**physics**

When a 58g tennis ball is served, it accelerates from rest to a speed of 45m/s. The impact with the racket gives the ball a constant acceleration over a distance of 44cm. What is the magnitude of the net force acting on the ball?

*February 12, 2012*

**Physics**

A 343-kg boat is sailing 16.2° north of east at a speed of 1.98 m/s. Thirty seconds later, it is sailing 37.5° north of east at a speed of 3.76 m/s. During this time, three forces act on the boat: a 30.3-N force directed 16.2° north of east (due to an auxiliary ...

*February 12, 2012*

**physics**

An electron is a subatomic particle (m = 9.11 10-31 kg) that is subject to electric forces. An electron moving in the +x direction accelerates from an initial velocity of +5.21 105 m/s to a final velocity of +2.29 106 m/s while traveling a distance of 0.034 m. The electron'...

*February 12, 2012*

**physics**

Thank You

*February 11, 2012*

**physics**

As a moon follows its orbit around a planet, the maximum gravitational force exerted on the moon by the planet exceeds the minimum gravitational force by 9.8%. Find the ratio rmax/rmin, where rmax is the moon's maximum distance from the center of the planet and rmin is the...

*February 11, 2012*

**physics**

As a moon follows its orbit around a planet, the maximum gravitational force exerted on the moon by the planet exceeds the minimum gravitational force by 9.8%. Find the ratio rmax/rmin, where rmax is the moon's maximum distance from the center of the planet and rmin is the...

*February 9, 2012*

**Physics**

A 343-kg boat is sailing 16.2° north of east at a speed of 1.98 m/s. Thirty seconds later, it is sailing 37.5° north of east at a speed of 3.76 m/s. During this time, three forces act on the boat: a 30.3-N force directed 16.2° north of east (due to an auxiliary ...

*February 9, 2012*

**Physics**

The lob in tennis is an effective tactic when your opponent is near the net. It consists of lofting the ball over his head, forcing him to move quickly away from the net (see the drawing). Suppose that you lob the ball with an initial speed of 16.0 m/s, at an angle of 47.0°...

*February 9, 2012*

**physics**

An electron is a subatomic particle (m = 9.11 10-31 kg) that is subject to electric forces. An electron moving in the +x direction accelerates from an initial velocity of +5.21 105 m/s to a final velocity of +2.29 106 m/s while traveling a distance of 0.034 m. The electron'...

*February 9, 2012*

**Physics**

An airplane with a speed of 76.8 m/s is climbing upward at an angle of 48° with respect to the horizontal. When the plane's altitude is 560 m, the pilot releases a package. (a) Calculate the distance along the ground, measured from a point directly beneath the point of...

*February 8, 2012*

**physics**

The lob in tennis is an effective tactic when your opponent is near the net. It consists of lofting the ball over his head, forcing him to move quickly away from the net (see the drawing). Suppose that you lob the ball with an initial speed of 16.0 m/s, at an angle of 47.0°...

*February 8, 2012*

**chemistry**

What are the acids in the house?

*January 31, 2012*

**Physics**

Derive an expression for the vertical position of a projectile in terms of its horizontal position. This sometimes called parametric equation or path equation for the projectile. I don't know how to get it please help. Thank you.

*January 30, 2012*

**Physics**

An 18-year-old runner can complete a 10.0-km course with an average speed of 4.39 m/s. A 50-year-old runner can cover the same distance with an average speed of 4.27 m/s. How much later (in seconds) should the younger runner start in order to finish the course at the same time...

*January 29, 2012*

**Physics**

Can you think of any ways to measure instantaneous speed directly?

*January 29, 2012*

**Physics**

What equation gives the velocity as a function of time for an object with constant acceleration?

*January 29, 2012*

**physics**

What equation gives the position as a function of time for an object with constant acceleration?

*January 29, 2012*

**physics**

A dynamite blast at a quarry launches a chunk of rock straight upward, and 2.0s later it is rising at a speed of 15m/s. Assuming air resistance has no effect, calculate its speed A) at launch and B) 5.0s after lauch

*January 29, 2012*

**Physics**

In a historical movie, two knights on horseback start from rest 88.0m apart and ride directly toward each other to do battle. Sir George's acceleration has a magnitude of 0.300m/s (squared), While Sir Alfred's has a magnitude of 0.200m/s (squared). Relative to Sir ...

*January 29, 2012*

**physics**

(a) Just for fun, a person jumps from rest from the top of a cliff overlooking a lake. In falling through a distance H, she acquires a certain speed v. Assuming free-fall conditions, how much farther must she fall in order to acquire speed 2v? Express your answer in terms of H.

*January 20, 2012*

**physics**

Two cars cover the same distance in a straight line. Car A covers the distance at a constant velocity. Car B starts from rest and maintains a constant acceleration. Both cars cover a distance of 487 m in 216 s. Assume that they are moving in the +x direction. Determine (a) the...

*January 20, 2012*

**physis**

The magnitudes of the four displacement vectors shown in the drawing are A = 13.0 m, B = 11.0 m, C = 12.0 m, and D = 27.0 m. Determine the magnitude and directional angle for the resultant that occurs when these vectors are added together.

*January 20, 2012*

**Physics**

A jetliner, traveling northward, is landing with a speed of 67 m/s. Once the jet touches down, it has 765 m of runway in which to reduce its speed to 5.1 m/s. Compute the average acceleration (magnitude and direction) of the plane during landing (take the positive direction to...

*January 20, 2012*

**physics**

An 18-year-old runner can complete a 10.0 km course with an average speed of 4.58 m/s. A 50-year-old runner can cover the same distance with an average speed of 4.36 m/s. How much later (in seconds) should the younger runner start in order to finish the the course at the same ...

*January 20, 2012*

**algebra**

Which is an example of the commutative property? A. –8 + (–13) = –13 + (–8) B. 11 + (–14 + 5) = (11 + (–14)) + 5 C. 16 + (–16) = 0 D. –(22 + 1) = –22 + (–1)

*January 17, 2012*

**football names**

What is the football name of this clue, seven squared?

*January 1, 2012*

**Chem**

using math expressions, define the following: Ka,pKa, pKb, Kb and pKw

*January 1, 2012*

**biostatistics**

A clinical trial is run to assess the effects of different forms of regular exercise on HDL levels in persons between the ages of 18 and 29. Participants in the study are randomly assigned to one of three exercise groups - Weight training, Aerobic exercise or Stretching/Yoga...

*November 26, 2011*

**statistics**

Suppose that in the aerobic exercise group we also measured the number of hours of aerobic exercise per week and the mean is 5.2 hours with a standard deviation of 2.1 hours. The sample correlation is -0.42. a)Is there evidence of a significant correlation between number of ...

*November 26, 2011*

**biostatistics**

7. Consider again the data in problem #6. Suppose that in the aerobic exercise group we also measured the number of hours of aerobic exercise per week and the mean is 5.2 hours with a standard deviation of 2.1 hours. The sample correlation is -0.42. a)Is there evidence of a ...

*November 26, 2011*

**biostatistics**

8. The following data were collected in a clinical trial to compare a new drug to a placebo for its effectiveness in lowering total serum cholesterol. Generate a 95% confidence interval for the difference in mean total cholesterol levels between treatments. New Drug (n=75) ...

*November 26, 2011*

**biostatistics**

Suppose we want to design a new placebo-controlled trial to evaluate an experimental medication to increase lung capacity. The primary outcome is peak expiratory flow rate, a continuous variable measured in liters per minute. the primary outcome will be measured after 6 months...

*November 19, 2011*

**history**

How did african slavery contributed to the economic growth of the british economy

*November 15, 2011*

**Math**

(x-A)(x+A)= x^2 - A^2 hence A^2 =x^2 - 2009 =16 A = square root of 16 = +4, -4

*November 14, 2011*

**Comm II**

When you write a definition of something, I was taught in school that you should not use the word you are defining in the definition. Does this still apply throughout a definition essay? If so, then how?

*November 9, 2011*

**biostatistics**

A studyis run to estimate the mean total cholesterol level in children 2 to 6 years of age. A sample of 9 participants is selected and their total cholesterol levels are measured as follows: 185 225 240 196 175 180 194 147 223 Generate a 95% confidence interval for the true ...

*November 7, 2011*

**biostatistics**

among coffee drinkers, men drink a mean of 3.2 cups per day with a standard deviation of 0.8 cups. Assume the number of coffee drinks per day follows a normal distribution. a. What proportion drinks 2 cups per day or more? b. What proportion drink no more than 4 cups per day? ...

*November 4, 2011*

**CHEMISTRY!! NEED IMMEDIATE HELP PLEASE!!!**

a. Calculate the delta H, delta G, and equilibrium constant for the reaction of methane with Cl2 to give CH3Cl and HCl. Use the following information for your calculations: Bond Dissociation Energies: CH3-H (104.8kcal/mol), Cl-Cl(59.0 kcal/mol), CH3-Cl(85.0 kcal/mol), and H-Cl...

*October 30, 2011*

**business Math**

simple interest 2430 times 0.06 times 1/12

*October 30, 2011*

**algebra**

trains A and B are traveling in the same direction on paraleel tracks. Train A is traveling at 80 miles per hour and train B is traveling at 88 miles per hour. Train a passes a station at 5:10 P.M. If train B passes the same station at 5:40 P.M., at what time will train B ...

*October 23, 2011*

**Chemistry urgent**

How is pushing down the accelerator pedal resulting in a faster consumption of fuel in the engine concentration?

*October 23, 2011*

**Chemistry urgent**

How is pushing down the accelerator pedal resulting in a faster consumption of fuel in the engine concentration?

*October 23, 2011*

**Chemistry 10**

The accelerator pedal in the car is pressed, resulting in a faster consumption of fuel in the engine. Now according to previous answers to this question the answers concentration but I do not understand how. I though concentration is the amount of a substance dissolved in a ...

*October 23, 2011*

**calc**

a machine can produce 12 clay figure per hour.it costs $750 to set up the machine and $6 per hour to run the machine.each clay figure requires $2 of material to produce.if each clay figure will sell for $10 charged,express the revenue cost,and profit in producing x clay figure...

*August 26, 2011*

**calc**

water is stored in a tank in the shape of an interval cone of height 10ft and diameter 6ft.express the volume of water in the tank as a function of the height h of the water level.

*August 26, 2011*

**calc**

a cylindrical container with a circular base has a surface area of 64ft squared.express its volume as a function of its radius

*August 26, 2011*

**calc**

an open box is to be made from a 4 ft by 5 ft piece of cardboard by cutting out squares of equals sizes with width x ft from the four corners and bending up the flaps to form sides.express the volume of the open box as a function of x what is the domain of the function

*August 26, 2011*

**calc**

a closed box has a base twice as long as it is wide.if its volume is 100 in cubed,express its surface area as a function of the width x of its base.

*August 26, 2011*

**calc**

a 1 mile racetrack has two semicircula ends connected by straight lines.express the area enclosed by the track as a function of its semi circular radius.determine its domain.

*August 26, 2011*

**calc**

a 1 mile racetrack has two semicircula ends connected by straight lines.express the area enclosed by the track as a function of its semi circular radius.determine its domain.

*August 26, 2011*

**calculus**

a piece of wire 12 inches long is to be used to form a square and or a circle.determine a function that expresses the combined area of both figures.what is its domain?

*August 26, 2011*

**calculus**

a farmer has a 1500 feet of fencing in his barn.he wishes to enclose a rectangler pen,subdivided in two regions by a section of the fence down the middle,parallel to one side of the rectangle.express the area enclosed by the pen as a function of its width x.what is the domain ...

*August 26, 2011*

**english**

NO IDEA AT ALL

*August 4, 2011*

**com 155**

Review the passage below, which contains 20 errors. Identify these errors by marking each of the errors in bold, and make your correction in parentheses after the error. Example: My cars interior is black. This must be marked as follows: My cars (car’s) interior is black...

*July 21, 2011*

**math**

Rewrite with positive exponents. Assume that even roots are of nonnegative quantities and that all denominators are nonzero. (2x/y2)^-4

*June 21, 2011*

**math**

Solve using the elimination method. Show your work. If the system has no solution or an infinite number of solutions, state this. -15r + 12s = 24 30r – 24s = 48

*June 21, 2011*

**english**

One of the four underlined sections may mark an error in punctuation. Choose the option that marks the error in punctuation. If there is no error, choose No error. For most of us who are not reading specialists, learning to read is a mysterious process; why a child is ready to...

*June 15, 2011*

**Punctuation**

Paloma did not make it to work for her car, broke down on the freeway. Is this better? The hardware store down the street, which had been paved recently, is open until midnight five days a week. Many students anticipate spring break but, Luis looks forward to winter vacation ...

*May 11, 2011*

**Punctuation**

Is this correct? Even though it is almost summer, we still have overcast skies and light rain. The neighbors’ new dog is, small, quiet and shy. The oil from Eucalyptus trees, which are native to Australia, is known for its medicinal properties. Paloma did not make it to ...

*May 11, 2011*

**english**

Paloma did not make it to work for, her car broke down on the freeway.

*April 25, 2011*

**spanish**

fill in the blank ?es el libro _____profesor? no, es mi libro. la clase ____ profesor de español es muy interesante. la mochila _____muchacha es rosado. yo soy ___ estados unidos. ?son los bolígrafos de teresa? no, son ____ profesora. please help

*April 11, 2011*

**spanish**

miro ______ pizarra. what goes in the blank? voy _______ escuela. voy__________ laboratorio. escucho ___ profesor cuando el habla miro ____ alumno guapo. :)

*April 11, 2011*

**Reading Comp.**

A recent study conducted by British zoologists concludes that, like birds and other animals, human beings possess a “homing instinct.” The study showed that this homing instinct or natural sense of direction is based on some kind of perception of magnetic fields. ...

*March 28, 2011*

**English**

Thank you!!!

*March 12, 2011*

**English**

Thanks, I need some goos point to make it better.

*March 12, 2011*

**English**

It is very important because Canada is a nation of immigrants. I believe that there is an opportunity to learn from everyone in this world and everyone contributes to making Canada the country that it is.

*March 12, 2011*

**English**

why diversity is or is not an important element of our Canadian culture in your opinion?

*March 12, 2011*

**Penn Foster**

i need the answer from 00701300

*March 8, 2011*

**math**

What is the meaning of angle of depression and angle of elevation?

*February 17, 2011*

**geograohy**

state if each sentences is climate or weather the is so hot but last night was cool

*February 15, 2011*

**Project Management**

Search the web for project planning tools and describe at least 2. download a demo to two, and build a project so you can see the different PM charts(Grantt,CPM, Pert, etc.). Comment on the ease in in which you were able to build each of the charts. Which tool would you ...

*February 15, 2011*

**grammar**

Is this correct? Even though it is almost summer, we still have overcast skies and light rain

*January 23, 2011*

**statistic**

A die is rolled once. The probability of obtaining an odd number is

*January 15, 2011*

**Chemistry Lab**

Which of the following would NOT be a factor for a solute to dissolve in water? A. A solute separates into ions which are supported by hydration. B. Electrostatic attraction between the partially charged atoms in water molecules and the solute. C. A solute has a higher formula...

*January 12, 2011*

**Chemistry Lab**

Which of the following would NOT be a factor for a solute to dissolve in water? A. A solute separates into ions which are supported by hydration. B. Electrostatic attraction between the partially charged atoms in water molecules and the solute. C. A solute has a higher formula...

*January 12, 2011*

**Chemistry Lab**

You are given 350 mL a stock solution of 1.66E-02 M benzoic acid, MW = 122.125 g/mol. Answer the following questions. A. What is the number of moles present in the original stock solution? B. You need to dilute the benzoic acid stock solution to 1.24E-03 M. If you need 455 mL ...

*January 11, 2011*

**Chemistry Lab**

You are given 350 mL a stock solution of 1.66E-02 M benzoic acid, MW = 122.125 g/mol. Answer the following questions. A. What is the number of moles present in the original stock solution? B. You need to dilute the benzoic acid stock solution to 1.24E-03 M. If you need 455 mL ...

*January 11, 2011*

**Chemistry Lab**

How many milligrams are there in 1.57 kg?

*January 11, 2011*

**soc 120**

The correct answer for #4 is misinterprets key terms --

*December 12, 2010*

**statistic**

the mean of adult men is 172 pounds with a standard deviation of 29 pounds. ask 20 men thier weight and use excel to calculate the mean. test the hypothesis that the mean is not 172 pounds at the .10 significance level. and how many men should be sampled if you want to be 98% ...

*December 4, 2010*

**english**

how do a write a paragraph on how i plan to obtain my goal as a Doctor?

*November 30, 2010*

**11th grade**

Sodium Vapor lamps emit a characteristic yellow light . What can we deduce about sodium atoms, based on this observation?

*November 1, 2010*

**Chemistry**

Sodium Vapor lamps emit a characteristic yellow light . What can we deduce about sodium atoms, based on this observation? Please help!!

*November 1, 2010*

**English**

Supposedly? So does that mean that they could, without due cause? and the employee could do nothing about it?

*October 27, 2010*

**English**

Okay. And job rights these days would be extremely different, yes?

*October 27, 2010*

**English**

What are the job rights of Willy Loman? What are his rights, as an employee, when he got fired? Were there any rights at that time?

*October 27, 2010*

**English**

**Of Willy Loman, sorry.

*October 27, 2010*

**English**

In Arthur Miller's "Death of a Salesman" What were the job rights, or Willy Loman?

*October 27, 2010*

**4th grade**

This is hard for me but I also thing is 131 because I did every thing I had to do. ☁☁☁☁☁☁☁ ☁🎀🎀☁🎀🎀☁ 🎀🎀🎀🎀🎀🎀🎀 🎀🎀&#...

*October 8, 2010*

**Social Studies**

How can the World-System theory be applied to the events in Timor Leste since August 1999?

*September 29, 2010*

**Elements of Psychology**

I need help on these questions. My answers have the < by them 1. In a typical neuron, sheaths of fatty tissue called _______ surround the axon. A. terminals C. synapse B. dendrites D. myelin <C 2. You’ve already gathered data to measure the relationship between ...

*September 16, 2010*

**arithmetic**

james has a metal fame with an 8.32 inch perimeter. if the sides are .04 inches thick, what is the perimeter of the inside of the frame

*September 13, 2010*

**algebra**

(2x^2-3x+1)(x^2+x-2)

*August 31, 2010*

**statistics**

2. Assume that the population proportion of adults having a college degree is 0.35. A random sample of 200 adults is to be selected to test this claim. A) What is the shape, mean, and standard deviation of the sampling distribution of the sample proportion for samples of size ...

*August 17, 2010*

**Math**

(-3)-[3(-4)+7=

*July 20, 2010*

**statistics**

A confidence interval for the mean is a range ìlower < ì <ìupper where the lower bound is the smallest value of ì that we expect and the upper bound is the largest value of ì that we expect”(Doane-Seward,2007). “If we wanted a...

*April 30, 2010*

**pure math 30**

the graph y=x^3-4x^2+x+6 is stretched horizontally by a factor of 2 about the line x=4. what is the resulting equation

*April 6, 2010*

**physical science**

find the net force produced by a 40 Newton force and a 50 Newton force in each of the following cases: Both forces act in the same direction. Both forces act in opposite directions.

*March 26, 2010*

**Chemistry**

I am about to do an extraction experiment, and needed help with a question to improve my understanding. Any help appreciated. 1. You have 150 ml of a solution of benzoic acid in water estimated to contain about 5g of the acid. The distribution coeffcient of benzoic acid in ...

*March 12, 2010*

**Chem again**

Oh I just realized, that was a typo, I meant to divide it by the original mass of 5.0 getting 89.4%

*March 8, 2010*