Sunday

May 1, 2016
Total # Posts: 274

**Physics**

HELP! A tennis ball is attached to a .8m long string whirled around in a circle with a constant frequency of 1.2 Hz. What is the linear(tangential) velocity of the tennis ball?
*March 12, 2012*

**physics**

A wooden box weighing 271 N is pushed across the floor by a workman who exerts a horizontal force of 144 N. If the force of friction between the box and the floor is 28 N, what is the acceleration (in meters/second^2) of the box?
*March 7, 2012*

**Probability**

how many can 5 people be arranged in a row if the father is on the far right?
*February 25, 2012*

**Physics**

A vibration platform oscillates up and down with an amplitude of 10.2 cm at a controlled variable frequency. Suppose a small rock of unknown mass is placed on the platform. At what frequency will the rock just begin to leave the surface so that it starts to clatter?
*February 19, 2012*

**Physics**

Two electrons are fixed 2.99 cm apart. Another electron is shot from infinity and stops midway between the two. What is its initial speed?
*February 9, 2012*

**Physics**

you screwed buddy
*February 5, 2012*

**physics**

Kole is right but how would you find velocity
*February 5, 2012*

**Physics**

This question contains a graph: h t t p : / / i . i m g u r . c o m / Q z l x d . p n g
*February 3, 2012*

**Chemistry**

Calculate the heat released from 61.5 g of steam at 111 degrees C is converted to water at 39 degrees C. Assume the specific heat of water is 4.184 J/g*C, the specific heat of steam is 1.99 J/g*C and the enthalpy.H.vap= 40.79 KJ/mol of water
*January 26, 2012*

**Chemistry**

What is the Heat Change in kilojoules when 61.5 g of steam is cooled from 111 degrees C to 100 degrees C?
*January 26, 2012*

**Physics**

Figure (a) shows charged particles 1 and 2 that are fixed in place on an x axis. Particle 1 has a charge with a magnitude of |q1| = 12.0e. Particle 3 of charge q3 = +13.0e is initially on the x axis near particle 2. Then particle 3 is gradually moved in the positive direction ...
*January 20, 2012*

**Physics**

Figure (a) shows charged particles 1 and 2 that are fixed in place on an x axis. Particle 1 has a charge with a magnitude of |q1| = 12.0e. Particle 3 of charge q3 = +13.0e is initially on the x axis near particle 2. Then particle 3 is gradually moved in the positive direction ...
*January 20, 2012*

**Math**

What's the least common multiple of 2 and 2.5?
*January 19, 2012*

**Physics**

This problem contains a graph: h t t p : / / i . i m g u r . c o m / p s z e p . p n g
*January 19, 2012*

**Physics**

Here is the problem in image form: h t t p : / / i . i m g u r . c o m / g n 1 j R . p n g
*January 19, 2012*

**Physics**

Sphere W (with an initial charge of zero) is touched to sphere A and then they are separated. Next, sphere W is touched to sphere B (with an initial charge of -26e) and then they are separated. Finally, sphere W is touched to sphere C (with an initial charge of 46e), and then ...
*January 19, 2012*

**Physics**

They're all the same size.
*January 19, 2012*

**Physics**

Sphere W (with an initial charge of zero) is touched to sphere A and then they are separated. Next, sphere W is touched to sphere B (with an initial charge of -26e) and then they are separated. Finally, sphere W is touched to sphere C (with an initial charge of 46e), and then ...
*January 19, 2012*

**homework**

every yellow marble is expensive.one -half the orange marbles are expensive.one -half of all expensive marbles are yellow. there are 40 yellow marbles and 25 expensive marbles that are niether yellow nor orange. how many orange marbles are there?
*October 30, 2011*

**Statistics**

Suppose you know ó and you want an 85 percent confidence level. What value would you use to multiply the standard error of the mean by?
*October 23, 2011*

**Electric Fields**

In a particular region of Earth's atmosphere, the electric field above Earth's surface has been measured to be 151 N/C downward at an altitude of 280 m and 167 N/C downward at an altitude of 430 m. Calculate the volume charge density of the atmosphere, assuming it to ...
*October 9, 2011*

**Physics**

A chair with a mass of 30.0kg is shot with a 10g bullet traveling at a speed of 250m/s. The bullet goes 6cm into the chair. The given kinetic friction for for this problem is .2. How far does the chair slide in cm?
*October 2, 2011*

**Physics**

The coefficient of kinetic friction for a 22 kg bobsled on a track is 0.15. What force is required to push it down a 6.0° incline and achieve a speed of 64 km/h at the end of 75 m?
*October 2, 2011*

**Physics**

A person throws a ball upward into the air with an initial velocity of 15.0 m/s. Calculate the following: a.) how high it goes. b.) how long the ball is in the air before it comes back to his hand. c.) at what time(s) will the ball pass a point 8.00 m. If you got multiples ...
*September 27, 2011*

**Physics**

Units count. Show all steps, not just the numerical substitutions. Show the equations you used. No information is missing. A person throws a ball upward into the air with an initial velocity of 15.0 m/s. Calculate the following: a.) how high it goes. b.) how long the ball is ...
*September 26, 2011*

**Modern Physics**

(7) Show that if a particle moves at an angle θ with respect to the x-axis with speed u in frame S, then it moves at an angle θ′ with the x′-axis in frame S′ with tanθ′ = sinθ /( γ(cos θ − v/u)) Assume that S′ ...
*September 18, 2011*

**University Physics**

If vector B is added to vector C = 6.7 + 6.9, the result is a vector in the positive direction of the y axis, with a magnitude equal to that of vector C. What is the magnitude of vector B?
*September 6, 2011*

**University Physics**

If is added to = 6.7 + 6.9, the result is a vector in the positive direction of the y axis, with a magnitude equal to that of . What is the magnitude of ?
*September 6, 2011*

**physics**

Determine the stopping distances for a car with an initial speed of 93 km/h and human reaction time of 3.0 s for the following accelerations: -4.00 m/s^2 -8.00 m/s^2
*August 19, 2011*

**physics (non-calc)**

A particle of charge 2.5x10(^-6)C is moving at 1000 m/sec in a direction 30 degrees North of east. At the location of the particle the magnetic field has size 0.2 T. The particle is experiencing an instantaneous magnetic force (due to this sheild) of 1.71x10(^-4) newtons ...
*June 7, 2011*

**game theory**

Two companies, A and B, produce widgets. Each can produce 0, 1, 2, 3, or 4 widgets (they canâ€™t produce fractions of widgets). Let X be the number of units produced by A, and Y be the number of units produced by B. Given X and Y, widgets will sell at a price ...
*May 5, 2011*

**economics**

Two companies, A and B, produce widgets. Each can produce 0, 1, 2, 3, or 4 widgets (they canâ€™tÂ produce fractions of widgets). Let X be the number of units produced by A, and Y be the number of units produced by B. Given X and Y, widgets will sell...
*May 5, 2011*

**Chemistry**

Trista is almost correct. However she failed to realize that the problem called for 100 mg which is equal to 0.1 grams. This means that (7.05x10^-3)g/L / 0.1g = 0.0705/1L (Where the L is in the denominator). So in order to finalize this problem all you have to do is take the ...
*April 24, 2011*

**Math**

How many ml are there in .032L ?
*April 22, 2011*

**Physics **

Can someone please help me? The brakes of a truck cause it to slow down by applying a retarding force of 2.60 103 N to the truck over a distance of 930 m. What is the magnitude of the work done by this force on the truck? Is the work positive or negative? Explain Why?
*March 15, 2011*

**Calculus**

Find the equation of the plane through (1,2,-2) that contains the line x = 2t, y = 3 - t, z = 1 +3t
*February 17, 2011*

**Calculus 3**

Show that if a, b, c are in V3, then (a x b) dot [(bxc)x(cxa]) = [a dot (b x c)]^2 I dont know what properties to use
*February 8, 2011*

**Vectors**

Show that if a, b, c are in V3, then (a x b) dot [(bxc)x(cxa]) = [a dot (b x c)]^2 I dont know what properties to use
*February 8, 2011*

**physics**

The answer is 200N in the sense that an increase in force will produce an increase in the acceleration.
*November 21, 2010*

**Physics**

Nevermind. The answer is 250 degrees Celsius. Duh!
*November 16, 2010*

**Physics**

(brass diameter)*(1+(brass coefficient)*(change in brass temperature)) = (iron diameter)*(1+(iron coefficient)*(change in iron temperature)) where: brass coefficient = 19*10^-6 K^-1 iron coefficient = 12*10^-6 K^-1
*November 16, 2010*

**Physics**

A brass plug is to be placed in a ring made of iron. At 20 degrees Celsius, the diameter of the plug is 8.737 cm and that of the inside of the ring is 8.723 cm. They must both be brought to what common temperature in order to fit? (ANSWER: -210 degrees Celsius) What if the ...
*November 16, 2010*

**Algerbra**

f(x)=4x^2+7x-5 and g(x)=-9x^2+3x-14
*November 12, 2010*

**Physics - Buoyancy**

A scale reads 20.3 N when an object is not submerged in water and 20.0 N when the object is (completely) submerged in water. What is the specific gravity of the object?
*November 11, 2010*

**Chemstry**

This implies that the double and triple bond are adjacent to eachother, so that would give the N an expanded octet of 10 electrons, but I thought that only happened after P?
*November 9, 2010*

**Chemstry**

What is the structure of N4O, where the 3 nitrogen bonds have different bond lengths and the N=O bond is a double bond. I just dont get it
*November 9, 2010*

**chemistry**

Am I right with my answer?
*November 8, 2010*

**chemistry**

A tragedy hits a small town. The elementary school explodes into flames trapping several classes of second graders. Because the volunteer fire department will take too long to get there, teachers and classified staff remove all the children to safety without considering the ...
*November 8, 2010*

**sience**

If it happens that a neurotransmitter binds to a receptor site and produces a negative voltage shift, the probability: that the neurons are densely connected decreases. of an excitatory response increases. that the receiving neuron will fire decreases. that the transmitting ...
*November 8, 2010*

**general**

Neurons receive communication through dendrites which act as antennae. Transmitting these initial messages to other neurons is the function of the: cell body. synapse. cerebellum. axon. Im between A and D. Please help.
*November 8, 2010*

**Physics**

A 13 cm long animal tendon was found to stretch 3.8 mm by a force of 13 N. The tendon was approximately round with an average diameter of 9.0 mm. Calculate the elastic modulus of this tendon.
*October 28, 2010*

**social studies**

how much respect is given to older people
*October 23, 2010*

**Physics**

Estimate the work you do to mow a lawn 14m by 23m with a 0.5m-wide mower. Assume you push with a force of about 15N.
*September 29, 2010*

**Physics**

Estimate the work you do to mow a lawn 14m by 23m with a 0.5m-wide mower. Assume you push with a force of about 15N.
*September 28, 2010*

**Physics**

h t t p : / / b i t . l y / 9 S F F F o a) What is the minimum value of F needed to move the two blocks? b) If the force is 10% greater than your answer for (a), what is the acceleration of each block?
*September 19, 2010*

**Physics**

Three Coulombs of charge flow through a wire in 150 ms. If the current ceases to flow (goes to zero Amps) for the following 850 ms, what is the average current over this one-second period?
*September 19, 2010*

**Physics**

A 48V battery delivers power to a golf cart. The golf cart drives for 45 seconds while the batteries deliver 12A of current. How much energy (in Joules) is delivered during the drive?
*September 18, 2010*

**Physics**

A 1100 kg car is moving toward the north along a straight road at a speed of 20.0 m/s. The driver applies the brakes and the car comes to rest in a distance of 140 m. (a) If the road is completely level, what is the constant force applied to the car to bring it to rest? (...
*September 16, 2010*

**Physics**

A 1100 kg car is moving toward the north along a straight road at a speed of 20.0 m/s. The driver applies the brakes and the car comes to rest in a distance of 140 m. (a) If the road is completely level, what is the constant force applied to the car to bring it to rest? (...
*September 16, 2010*

**Physics**

A sprinter starts from rest in a 100-meter race, accelerates to his full running speed of 10.3 m/s in 1.15 seconds (assume constant acceleration) and continues at that speed for the rest of the race. (a) How far did he run before attaining his full speed? (b) What was his ...
*September 16, 2010*

**Physics**

{ The subscripts are in curly brackets } A mass m is at rest on a horizontal frictionless surface at t=0. Then a constant force F{0} acts on it for a time t{0}. Suddenly, the force doubles to 2F{0} and remains constant until t=2t{0}. Determine the total distance D traveled ...
*September 16, 2010*

**Physics**

A child on a sled reaches the bottom of a hill with a velocity of 12.0 m/s and travels 22.0 m along a horizontal straightaway to a stop. If the child and sled together have a mass of 59.0 kg, what is the magnitude of the average retarding force on the sled on the horizontal ...
*September 14, 2010*

**Physics**

Estimate the average force exerted by a shot-putter on a 6.5 kg shot if the shot is moved through a distance of 2.7 m and is released with a speed of 11 m/s.
*September 14, 2010*

**Physics**

1.) Describe the proper way to use a meter stick and why this technique is necessary (include an explanation of uncertainty). 2.) What is the difference between percent error and standard error?
*September 8, 2010*

**chem - br bob is this right**

What is the pH of a solution prepared by adding 4.000 grams of NaOH to a 50.00 mL of a buffer that is 2.00 molar both in acetic acid and sodium acetate? (Assume final volume is still 50.00 mL) * chem - DrBob222, Wednesday, April 21, 2010 at 10:52pm * chem - phil, Wednesday, ...
*April 21, 2010*

**chem**

i did .1 mols of AC- + .1 mols of OH gives me .2 mols of AC. the .2 mols of AC reacts with water AC- + H20---> OH- + HAC so the M is .2/.05 L = 4M to solve for the OH conc i did X^2 / 4 = 5.6 x 10^-10. and solving for the pH i get 9.675 is this right?
*April 21, 2010*

**chem**

What is the pH of a solution prepared by adding 4.000 grams of NaOH to a 50.00 mL of a buffer that is 2.00 molar both in acetic acid and sodium acetate? (Assume final volume is still 50.00 mL)
*April 21, 2010*

**chem**

I dont think this would be correct because The solution you are proposing would have a pH over 12.
*April 8, 2010*

**chem**

how many mL of .100 M of acetic acid and .100 M of NaOH, would be need to make the volume 1.0 liters and have a pH7.00 if Ka=1.8x10^-5 please write out the steps or eq for me im gettin stuck
*April 8, 2010*

**Biology**

37 is a and 38 is i think a and b
*March 17, 2010*

**Math**

Yes "A" has reflective symmetry, not rotational symmetry.
*March 11, 2010*

**physics**

The mass times the coefficient of friction
*March 3, 2010*

**math**

Two angles are complementary. THe sum of the measure of the first angle and one forth of the second angle is 58.5 dagrees. Find the measure of the angles.
*January 31, 2010*

**math**

20% of num is x. the num is 4 more than x . what's the number.
*January 27, 2010*

**chemistry**

How many Ca +2 ions in 40.08g of CaCO3 (Calcium Carbonate) I'm unsure on how to approach this problem and set it up.
*January 21, 2010*

**accounting**

Your rich godfather has offered you a choice of one of the three following alternatives: $10,000 now; $2,000 a year for eight years; or $24,000 at the end of eight years. Assuming you could earn 11 percent annually, which alternative should you choose? If you could earn 12 ...
*January 10, 2010*

**Physics**

Please respond to my previous post.
*January 10, 2010*

**Physics**

Now I'm confused. Why does changing the direction of a force double it? I'm also confused about whether the tension is a reaction to the weight of the tire and the boy or the force that the boy pulls down on the rope with. Also if the force in the free body diagram of ...
*January 9, 2010*

**Physics**

Ok, I think I got it. Are these free body diagrams correct? (ignore the dots) TIRE+BOY: T F |.| .| W FREE END: .T .| .| .F SYSTEM: .F .| .| .T.....(This tension is down) T.F....(This tension is up) |.| .| .W CANCELING TENSIONS: 2F | | W 2F=W so F=(1/2)W
*January 9, 2010*

**Physics**

A boy sits in a tire that is attached to a rope that passes over a pulley fastened to the ceiling and then passes back down to the boy's hands. The weight of the boy plus the tire is W. The force with which the boy must pull on the free end of the rope to support his ...
*January 9, 2010*

**probability**

how many ways can the 5people be arranged in a row if the father is on the far right?
*January 1, 2010*

**Physics**

Hi maybe someone can help me out, since my teacher isn't available today and this is due tonight :D. Find the heat that flows in 1.0 s through a lead brick 17 cm long if the temperature difference between the ends of the brick is 9.5 C. The cross-sectional area of the ...
*December 10, 2009*

**Physics**

I'm not sure how to do the last problem in this pdf: h t t p : / / t i n y u r l . c o m / y 9 q f 4 7 4 Any help would be appreciated. Thank you!
*December 9, 2009*

**macroecon**

If the MPC equals.7 and the MPI equals .1 then the varible net export spending multiplier equals?
*November 8, 2009*

**french**

we have been given a text and have to find words in it. we have to find the word bothers/upsets all i know is that it begins wit 'in' could it be indispose as it is the only word beginning with it we also have to find (here)encounter an it begins with 'conn' ...
*November 7, 2009*

**Physics**

How would someone calculate the average velocity of something from a velocity vs. time graph?
*October 18, 2009*

**Physics**

Ok so I got the first and last parts correct from what i did, but the second part is still messing me up. Do i enter 1/2 the time i calculated in the first question?
*October 18, 2009*

**MICROBIOLOGY**

WHICH IS /ARE COMPLEMENTARY TO 5' AGGCUAAC 3' 1. 5'TCCGATTG3' 2. 3'TCCGATTC5' 3. 5'CTTAGCCT3' 4.3'TAAGCTTA5' 5. 3'TCCGATTG5' AND 5'GTTAGCCT3'
*October 3, 2009*

**MICROBIOLOGY**

WHICH IS A RNA MOLECULE AGCCTAC GGGCCCA GCCCUUA
*October 3, 2009*

**social life**

What aspects of social life do you expect not to undergo substantial change prior to the middle of the 21st century?
*August 10, 2009*

**MBA Econ**

Well why didn't he just sell the scrap wood? It's not economically efficient if he throws out something he could sell. And yes, of course it depends how much it cost those managers and workers in time to save the $7000 and what else could they have been working on.
*May 20, 2009*

**Calc**

i found x value of P how do I find the y value of P?
*April 5, 2009*

**Calc**

Find the point on the line 2 x + 7 y + 4 =0 which is closest to the point ( 0, 1 )
*April 5, 2009*

**Math**

Let xy = 5 and { dy }/{ dt } = 3. Find { dx }/{ dt } when x = 1.
*March 15, 2009*

**chemistry**

A researcher found that 11.56 g of lead sulfide, PbS, were formed when each of the following occurred: 10.0 g of lead reacted with 1.56 g of sulfur 10.0 g of lead reacted with 3.00 g of sulfur 18.0 g of lead reacted with 1.56 g of sulfur Explain these observations in terms of ...
*March 12, 2009*

**algebra**

7300@7% COMPOUNDED SEMIANNUALLY FOR 3 YRS
*February 27, 2009*

**english**

thank you. I read the night thoreau went to jail but I am still a little iffy on the whole personal witness thing
*February 3, 2009*

**english**

Hi can someone pelase help me explain this quote by Martin Luther King. In addition I also I need to know what the words "personal witness" in the quote mean. Thank you for all your help. "I became convinced that noncooperation with evil is as much a moral ...
*February 3, 2009*

**physics**

A standing is generated by two waves which have a velocity of 20 m/s, and go through 10 cycles in 2 seconds. How far is it from the 2nd node to the 7th node of standing wave?
*February 2, 2009*

**physics**

A standing is generated by two waves which have a velocity of 20 m/s, and go through 10 cycles in 2 seconds. How far is it from the 2nd node to the 7th node of standing wave?
*February 1, 2009*