Thursday

March 5, 2015

March 5, 2015

Total # Posts: 2,314

**physics**

a parent pushes a kid on a swing, A) If the child on the swing rises 2m above the lowest point during each cycle, what is her speed at the lowest point of the swing? B)If the beginning of a cycle (2m above the lowest point) the child is given a push so that her starting speed ...
*March 4, 2015*

**Physics**

A 39-turn circular coil of radius 3.20 cm and resistance 1.00 Ω is placed in a magnetic field directed perpendicular to the plane of the coil. The magnitude of the magnetic field varies in time according to the expression B = 0.010 0t + 0.040 0t2, where B is in teslas and...
*March 3, 2015*

**Physics**

A 24.8-g bullet is fired from a rifle. It takes 2.15 × 10-3 s for the bullet to travel the length of the barrel, and it exits the barrel with a speed of 778 m/s. Assuming that the acceleration of the bullet is constant, find the average net force exerted on the bullet.
*March 1, 2015*

**Physics**

The brakes of a truck cause it to slow down by applying a retarding force of 7760 N to the truck over a distance of 870 m. What is the work done by this force on the truck?
*March 1, 2015*

**Physics**

Power is Work/Time, or Force*Distance/Time. You have a velocity, which is Distance over time, so you need to find the force that the winch needs to pull the block upwards. That force is the frictional force (coefficient of friction* normal force) + the force of gravity down ...
*February 28, 2015*

**math**

in number 13,407.036 there are two 3's explain how the values of the 3's are related?
*February 27, 2015*

**math**

in the number 13,407.036 the are two 3's explain how the values of 3's are related?
*February 26, 2015*

**trig with enough info?**

Two oil Wells are 4 km and 6 km from the river. The points along the river are 8 km apart. Find the common loading point on the river, using the shortest amount of pipe.
*February 25, 2015*

**trig**

Two oil Wells are 4 km and 6 km from the river. The points along the river are 8 km apart. Find the common loading point on the river.
*February 25, 2015*

**Physics**

What is the wavelength of visible light emit- ted at 4.2 × 108 MHz?
*February 20, 2015*

**MATH**

determine the average savings balance on a particular day. error of tolerance is 50. what is the minimum number of accounts he must sample to construct a 95% confidence interval. the standard deviation is 350
*February 19, 2015*

**Prob/Stats**

determine the average savings balance on a particular day. error of tolerance is 50. what is the minimum number of accounts he must sample to construct a 95% confidence interval. the standard deviation is 350
*February 19, 2015*

**Physics**

There are a few different horsepower definitions - imperial, metric, DIN etc but an average conversion factor is 1hp = 745W Generator input = 1500 * 745 W = 1117500W Generator output = 1117500W * 80.0% = 894000W (3 sig figs) Current = 894000W / 1910V = 468.06A
*February 16, 2015*

**Physics**

A spring with a spring constant of 40.1 N/m is attached to different masses, and the system is set in motion. What is its period for a mass of 2.8 kg?
*February 11, 2015*

**Physics **

A weight suspended from a spring is seen to bob up and down over a distance of 11 cm twice each second. What is its frequency? Answer in units of Hz. 002 (part 2 of 3) 10.0 points What is its period? Answer in units of s. 003 (part 3 of 3) 10.0 points What is its amplitude? ...
*February 6, 2015*

**Physics **

A weight suspended from a spring is seen to bob up and down over a distance of 11 cm twice each second.
*February 5, 2015*

**Math**

In “Adventures of Isabel,” how is the doctor different from Isabel’s other enemies—the bear, the witch, and the giant? He is Nice to Her He Frighten Her He gets killed He may be Real Witch one pls? I think It's The first one..
*February 2, 2015*

**physics**

A juggler tosses a ball h = 2 m into the air with one hand and catches it with the other hand at the same level. Neglecting air resistance, how long is the ball in the air?
*January 29, 2015*

**college mathematics 1**

describe the graph of g(x)=f(x)+1 relitave to f(x)
*January 29, 2015*

**Calculus**

A hot air ballon lifts off the earth 300m away from an observer and rises straight up at a rate of 80m/min. At what rate is the angle of inclination of the observers line of sight increasing at the time the balloon is 300, above the ground?
*January 29, 2015*

**Physics**

In an action movie, the heroine is supposed to jump with a motorcycle from the roof of one skyscraper to another one. The roof of the second skyscraper is h=9 meters lower, and the gap between the buildings is d=15 meters wide. Both roofs are horizontal and flat. Neglecting ...
*January 27, 2015*

**Physics**

A juggler tosses a ball h = 2 m into the air with one hand and catches it with the other hand at the same level. Neglecting air resistance, how long is the ball in the air?
*January 27, 2015*

**Physics**

If you throw a ball into the air at some angle with respect to the horizontal, which of the following statements about the ball is true? The acceleration is zero at the top of the motion The horizontal component of the velocity is zero at the top of the motion The velocity is ...
*January 27, 2015*

**Physics**

Pease evaluate the statements by choosing from these three statements Always true: the statement is true under any circumstances Not necessarily true: the statement may be true in some circumstances, but not in others Always false: under no circumstances is this true 1. If you...
*January 27, 2015*

**Physics**

The captain of a boat wants to travel directly across a river that flows due east with a speed of 1.09 m/s. He starts from the south bank of the river and wants to reach the north bank by travelling straight across the river. The boat has a speed of 6.44 m/s with respect to ...
*January 27, 2015*

**Physics**

The air speed indicator of a plane that took off from Detroit reads 349 km/h and the compass indicates that it is heading due east to Boston. A steady wind is blowing due north at 46.5 km/h. a) Calculate the speed of the plane with reference to the ground. b) If the pilot ...
*January 27, 2015*

**Physics**

A swimmer is heading straight for the other shore of a river with a velocity of vs=0.5 m/s relative to the water, but is carried away by the current, which has a velocity of vr=0.4 m/s. It takes her 20.6 s to get across. How far downstream does she end up?
*January 27, 2015*

**Physics**

During a long airport layover, a physicist father and his 8-year-old daughter try a game that involves a moving walkway. They have measured the walkway to be 41.5 m long. The father has a stopwatch and times his daughter. First, the daughter walks with a constant speed in the ...
*January 27, 2015*

**Physics **

A man in search of his dog drives first 13.3 mi northeast, then 17.3 mi straight south, and finally 6.85 mi in a direction 30.3° north of west. 1. a) What is the magnitude of his resultant displacement? 2. b) What is the direction of his resultant displacement? Express ...
*January 27, 2015*

**Physics**

A 26.3 g marble sliding to the right at 21.0 cm/s overtakes and collides elastically with a 13.3 g marble moving in the same direction at 12.2 cm/s. After the collision, the 13.3 g marble moves to the right at 23.7 cm/s. Find the velocity of the 26.3 g marble after the collision.
*January 27, 2015*

**Physics**

A 2170 kg car moving east at 10.5 m/s collides with a 3230 kg car moving east. The cars stick together and move east as a unit after the collision at a velocity of 6.00 m/s. a) What is the velocity of the 3230 kg car before the collision? Answer in units of m/s. 016 (part 2 of...
*January 26, 2015*

**Physics**

A railroad car with a mass of 2.33 × 104 kg moving at 3.71 m/s collides and joins with two railroad cars already joined together, each with the same mass as the single car and initially moving in the same direction at 1.44 m/s. a) What is the final speed of the three ...
*January 26, 2015*

**Physics **

A 26.3 g marble sliding to the right at 21.0 cm/s overtakes and collides elastically with a 13.3 g marble moving in the same direction at 12.2 cm/s. After the collision, the 13.3 g marble moves to the right at 23.7 cm/s. Find the velocity of the 26.3 g marble after the ...
*January 26, 2015*

**Physics**

Two carts with masses of 4.3 kg and 3.9 kg move toward each other on a frictionless track with speeds of 5.6 m/s and 5.0 m/s, respec- tively. The carts stick together after colliding head-on. Find their final speed.
*January 26, 2015*

**Physics **

A 2170 kg car moving east at 10.5 m/s collides with a 3230 kg car moving east. The cars stick together and move east as a unit after the collision at a velocity of 6.00 m/s. a) What is the velocity of the 3230 kg car before the collision?
*January 26, 2015*

**Physics **

A football punter accelerates a 0.53 kg foot- ball from rest to a speed of 8.6 m/s in 0.24 s. What constant force does the punter e
*January 25, 2015*

**Physics**

A 83.8 kg astronaut is working on the en- gines of a spaceship that is drifting through space with a constant velocity. The astronaut turns away to look at Earth and several sec- onds later is 39.6 m behind the ship, at rest relative to the spaceship. The only way to re- turn ...
*January 25, 2015*

**math**

The area is the trinomial and the side lengths are the binomials
*January 25, 2015*

**Science**

Every individual including young people can make decisions to use resources wisely use the terms reduce reuse and recycle to explain how the students in the image above can help minimize solid waste. HELP LAST DAY TO DO THIS I NEED AN ANSWER.
*January 22, 2015*

**physics**

A 10.7 kg bowling ball moves in a straight line at 4.26 m/s. How fast must a 2.55 g Ping-Pong ball move in a straight line so that the two balls have the same momentum?
*January 21, 2015*

**12 Math**

slope: 22 instantaneous: 22 1/2
*January 21, 2015*

**Physics**

Calculate the magnitude of the linear momen- tum for each of the following cases a) a proton with mass 1.67 × 10−27 kg mov- ing with a velocity of 6 × 106 m/s. Answer in units of kg · m/s.
*January 19, 2015*

**Physics**

Calculate the magnitude of the linear momen- tum for each of the following casesEarth (m = 5.98 × 1024 kg) moving with an orbital speed equal to 26200 m/s. Answer in units of kg · m/s.
*January 19, 2015*

**Physics **

A railroad car with a mass of 2.33 × 104 kg moving at 3.71 m/s collides and joins with two railroad cars already joined together, each with the same mass as the single car and initially moving in the same direction at 1.44 m/s.What is the final speed of the three joined ...
*January 19, 2015*

**ART PLEASE HELP!!!!**

Superhero by.Kiana S. This student most likely creates art based on all of the following except A.personal interests B.personal style C.skill set D.knowledge of art history
*January 14, 2015*

**english**

Hello Ski! did you by the way completed the test? if you did can you post answers that was correct?
*January 13, 2015*

**Math**

Eryn and seven of her friends go out to lunch. The total bill comes to $143.35. They decide to leave a 15% tip. Each person will contribute an equal amount to the total tip. Estimate what each person should contribute.
*January 7, 2015*

**math**

a piece of ribbon is cut into two shorter pieces in the ratio 2.8 : 1.25 The difference in the length of the shorter pieces is 80.6 cm. What is the length of the original piece?
*January 6, 2015*

**math**

Martha wrote the following inequality statement about the temperatures: -4.3<-2.91<5.7
*January 3, 2015*

**Math**

The mean of Susan's math and science scores is 74 points. The mean of her math and English scores is 83 points. How many more points did Susan score in English than in science?
*December 17, 2014*

**Math**

25(5) to 38(10) (5)(5)(5) to (2)(19)(2)(5) (5)(5) to (4)(19) 25 to 76
*December 11, 2014*

**trig**

She means it intersects at (-20/29,-21/29) x=-20/29 y=-21/29
*December 6, 2014*

**physics-finding velocity**

A small block of mass .450 kg is sliding down a ramp inclined at an angle of 53 degrees to the horizontal. it starts to slide from a vertical height of .65 meters. Find the Velocity when it slides off the ramp. The way I approached this problem was by sing Vf^2-VI^2=2ad. ...
*December 1, 2014*

**physics**

You take a pendulum clock to the moon, Assuming you do not change anything about the clock, will it still keep the right time? why?
*December 1, 2014*

**physics**

You have a pendulum clock which keeps using a bob on a long shaft. The clock is running slow, You can add or subtract mass from the bobs, or move the bob up and down on the shaft? What should you do to correct the time on the clock?
*December 1, 2014*

**physics**

You test a moon buggy on earth. When the buggy hits a bump, it oscillates up and down on its springs with a period of 4 seconds. Will the period be the same when buggy is used on the moon?
*December 1, 2014*

**chemistry**

If you place 10.0 L of propanol (C3H8O) in a sealed room that is 3 m long, 2.75 m wide, and 2.5 m high, will all the propanol evaporate? If some liquid remains, how much will there be? The vapor pressure of propanol is 10.7 torr at 25 °C, and the density of the liquid at ...
*November 30, 2014*

**Math**

What is the riddle for moving words
*November 29, 2014*

**Chemistry**

I must be going wrong somewhere. 1.3x.250 = .325 Mols KOH .325 Mols KOH = .325 Mols HBr Then I'm taking 350ml (.350) and multiplying it by .325 Mols HBr and I get .11375... That doesn't seem quite right. I really do appreciate your help. I never took chemistry in high ...
*November 29, 2014*

**Chemistry**

Let’s assume you have 250 ml of a 1.3M KOH solution and you want to neutralize it with the acid HBr. It takes 350 ml of the HBr solution to do so. What must have been the molarity of the HBr solution? HBr(aq) + KOH(aq) => KBr(aq) + H2O(l) The stoichiometry is already ...
*November 29, 2014*

**Chemistry**

Ok, thank you!
*November 29, 2014*

**Chemistry**

For an H+ concentration, [H+], of 4.3 x 10-4 M, would this be acidic, neutral or basic? Why? I'm assuming that because it is an H+ it would be acidic and H+ means acidic and OH- means base. Is this correct? And is there a better formula for this equation?
*November 29, 2014*

**Chemistry**

To make 250 ml of a 5%(w/v) calcium carbonate solution, how many grams of calcium carbonate will I need?
*November 29, 2014*

**physics **

we did a lab and my observation chart is like this when my mass is 1.4 kgs (height is 0.12m,distance is 1.0m,time is 0.87s,velocity is 1.1 m/s ,Eg is 1.6 and the Ek is 0.85) when my mass is 2.14 kgs(height is 0.12m,distance is 1.0m,time is 0.88s,velocity is 1.1 m/s ,Eg is 2.8 ...
*November 24, 2014*

**Maths**

I have 40 questions, 4 marks given for a correct answer, 2 marks deducted for each wrong answer and 1 mark deducted for for each answer not attempted I attempt 19 and score 25 marks.how many questions did I get right
*November 18, 2014*

**algebra**

student takes out two loans 1 at 10% and the other at 12 percent interest the 10 percent loan is $2000 more then the 12% loan and the total interest for one year is $430 how much is each loan?
*November 17, 2014*

**Science**

True/false Earth's atmosphere oceans and continents began to form during the first several hundred million years of the Precambrian time.
*November 17, 2014*

**Chemistry**

Dr. Bob, I am unable to see the answer you have provided? I'm not sure why, but I see "Bob Pursley answered your first post. It's below." The problem is, the is no post below.
*November 13, 2014*

**Chemistry**

I missed a few days of school due to a sick child. I'm reviewing for an exam and the following questions are giving me trouble as I wasn't there when they were reviewed in class. If possible, I need the answer and step-by-step process so I can see what what to do and ...
*November 13, 2014*

**Chemistry**

Thank you so much. This is sure to be very helpful!
*November 13, 2014*

**Chemistry**

Ah, this is what it means "below". In the second question I posted (above I guess) I rephrased my question for answer and all work. I'm really confused as to what your provided answer means as I missed these classes. I honestly have no idea what to make of the ...
*November 13, 2014*

**Chemistry**

I missed a few days of school due to a sick child. I'm reviewing for an exam and the following questions are giving me trouble as I wasn't there when they were reviewed in class. If possible, I need the step-by-step process. Thanks. 1.) If you put hydrogen peroxide on ...
*November 13, 2014*

**sixth grade math**

How to express 12/15 as a fraction, percent, and decimal. Someone please show me how to solve.
*November 12, 2014*

**sixth grade math**

The poster shows 12/15 games won so far. I need help on how to express as a fraction, percent, and as a decimal.
*November 12, 2014*

**sixth grade math**

The poster shows how many of its games the football team has won so far. Express this information as a fraction, a percent, and as a decimal. Can someone show me how to solve this problem?
*November 12, 2014*

**physics**

A 4.5 kg block is dropped onto a spring of spring constant 1861 N/m from a height of 1500 cm find the speed of the block when the compression of the spring is 12 cm. The acceleration of gravity is 9.81 m/s
*November 12, 2014*

**History**

What is the national monument of America?
*November 12, 2014*

**Physics-coefficient of friction**

What's the minimum coefficient of friction between the ladder (of length d) and the ground will keep it from slipping? (consider the wall frictionless) (θ=56.5 degrees) I think the formula is supposed to be mg L/2 sin y, but it does not provide a length, nor a mass. ...
*November 11, 2014*

**Physics- tension **

An 63 kg construction worker is sitting 2.0 m from the end of a 1435 kg steel beam to think about the state of the world. Find the tension in the cable that is supporting the beam. Am I required to use the formula T1=sin(theta)*m*g? I am not sure if the problem is similar to a...
*November 11, 2014*

**Physics- spring constant **

Astronauts are in space so there is no gravity, but they wish to weight themselves. The spring constant is 265 N/m. The question shows a graph; the y is the position in meters while the x is the seconds. I do not wish for an answer, but the way in which i'm supposed to ...
*November 11, 2014*

**Math**

A sea turtle laid 95eggs,each weighing 1 ounce.what is the total amount of weight in pound?
*November 10, 2014*

**English**

What is a metaphor for improvement?
*November 10, 2014*

**Physics**

A. You drag a suitcase of mass 19 kg with a force of F at an angle 41.3 degrees with respect to the horizontal along a surface with kinetic coefficient of friction 0.54. The acceleration due to gravity is 9.8 m/s^2. What is the normal force on the suitcase? Answer in units of ...
*November 6, 2014*

**physics-distance **

Here's a stationary bike. If you pedal such that the front wheel rotates at 6.9 rad/s, and that wheel's radius is half a meter, how far would you have gone in 35 minutes, if the bike where a non-stationary bike? (Assume a constant speed of rotation) I am not sure where...
*November 4, 2014*

**science**

Using the systematic method and information in the Appendices F and J (note that log value is given in Appendix J), determine [SCN-], [Hg2+], and [HgSCN+] at equilibrium when Hg(SCN)2(s) is dissolved in water.
*November 4, 2014*

**chemistry**

Propose methods for protecting the sodium hydroxide solution in the bottle and the buret from exposure to carbon dioxide in the air.
*November 3, 2014*

**Math**

A woman has money in two accounts. One account pays 7% annual interest, whereas the other pays 15% annual interest. If she has $1,500 more invested at 15% than she does at 7% and her total interest for a year is $1,545, how much does she have in each account? Please show the ...
*November 1, 2014*

**physics**

A skier leaves the starting gate at the top of a ski ramp with an initial speed of 4.00 m/s (Figure 6-41). The starting position is 120 m higher than the end of the ramp, which is 3.00 m above the snow. Find the final speed of the skier if he lands 145 m down the 20.0° ...
*October 31, 2014*

**english**

the air was thick and grey what else???
*October 29, 2014*

**english**

how can i describe polluted air using imagery
*October 29, 2014*

**grammar**

thanks
*October 29, 2014*

**grammar**

oops sorry that was a typo, it's supposed to be filled. "his eyes swollen and were filled with tears" OR his eyes suddenly got swollen and were filled with tears"
*October 29, 2014*

**grammar**

Does this sentence make sense? "His eyes swollen and were felled with tears."
*October 29, 2014*

**Chemistry**

Thanks
*October 29, 2014*

**Chemistry **

A sample of methane (CH4) gas contains a small amount of helium. Calculate the volume percentage of helium if the density of the sample is 0.70902 g/L t 273K and 1.00 atm. I know that the sample is at STP and that the 1 mole of gas under these conditions occupies 22.4L, but ...
*October 29, 2014*

**chemistry**

Just treat the 82.2 kJ as a product of the reaction and use stoichiometry to found out how many moles of methane were used like so... 82.2kJ x 2mol CH4/252.8 kJ = ? Then just multiply by the molar mass of methane (about 16.042g) to find how many grams of methane gas are ...
*October 29, 2014*

**Physics**

A 10 kg box is held 2 meters up a ramp that is inclined at 35 degrees. It is released frpm rest, slides down the ramp and across the floor. the coefficient of friction is 0.15. How far along the floor will the box slide?
*October 8, 2014*

**Social Studies**

thanks Ms. Sue
*October 7, 2014*

**Social Studies**

which of the following best describes the purpose of the U.S constitution? A. It restricts rights of citizens. B. it outlines how the government should make laws. C. it establishes a national bank. D. it outlines basic rights for the people of all nations of the world. B
*October 7, 2014*

**chemistry**

1. A sample weighing 1.30 mg was analyzed to determine the concentration of a certain compound (FW =292.16 g/mol) using UV/Visible spectrometry. First, the sample was dissolved in 5.00 mL volumetric flask. A 1.00 mL aliquot was drawn up, placed in a 10.0 mL volumetric flask ...
*October 2, 2014*

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