# When a tuning fork of unknown frequency is sounded simultaneously with a 512 Hz tuning fork, 20 beats are heard in 4.0 seconds. What are the possible frequencies of the unknown tuning fork?

7,356 questions, page 31
1. ## bio

if you were given a slide containing living cells of an unknown organism, how would you identify the cells as either plant or animal?

asked by ang on October 17, 2009
2. ## Physics

You are given two unknown point charges, Q1 and Q2. At a point on the line joining them, one-third of the way from Q1 to Q2 the electric field is zero . What is the ratio Q1/Q2?

asked by Anonymous on February 1, 2015
3. ## chemistry

If you were given an unknown solution, write the steps that would be needed to prove that a solution contained phosphate.

asked by AJ on January 5, 2011
4. ## chemistry

if 48.3 g of an unknown gas occupies 10.0 L at 40 degrees celsius and 3.10 atm, what is the molar mass of the gas?

asked by sherly on April 20, 2012
5. ## trigonometry

one leg of the right triangle is 10 cm and the hypotenuse is 20 cm longer than the other leg.Find the lenght of the unknown sides.

asked by joy on January 18, 2016
6. ## Chemistry

It takes 9.00 to raise the temperature of an 8.60 piece of unknown metal from 22 to 25.0. What is the specific heat for the metal?

asked by Tom on October 20, 2009
7. ## Math

I need help.I'm in 5th grade.The question is:12 less than the product of 5 and a number equals 8.What is the unknown number?Plz help

asked by Sydney on March 28, 2011
8. ## college

It takes 51.0 j to raise the temperature of an 8.60 g piece of unknown metal from 13.0 C to 25.0 C. What is the specific heat for the metal?

asked by Anonymous on October 27, 2010
9. ## Math

Translate the sentence into an inequality. Six increased by the product of a number and 10 is at most −16 . Use the variable x for the unknown number.

asked by Seth on February 11, 2015
10. ## math

The sum of 4 consecutive odd integers is -104. Find the integers with x for unknown numbers.

asked by math on January 31, 2011
11. ## chemistry

what is the molarity of an unknown acid if 40.5 ml. of the acid can be titrated to an end point by 20.5 mL. of 0.2250 M NaOH

asked by linda on April 11, 2016
12. ## physics

an object with a mass of 1500g accelerates 10.0 m/s2 when an unknown force is applied to it. What is the amount of the force?

asked by Jameel Williams on January 13, 2016
13. ## 7th science

acceleration=force divide by mass . How do you solve 20m/s2 =unknown divide by 0.15kg

asked by marie on January 21, 2012
14. ## chemistry

What is the molarity of an unknown acid if 40.5 ml of the acid can be titrated to an end point by 20.5 ml of 0.2250 M NaOH?

asked by bev on October 16, 2010
15. ## HIV and AIDS

The cure for HIV and AIDS is: a. unknown b. HIV vaccines c. drug "cocktails" d. antibiotics

asked by Anonymous on December 5, 2015
16. ## Math

What unknown number makes these equations true 353-203 = 353-200-

asked by Alyssa on October 5, 2016
17. ## Physics

On an unknown planet, a pendulum of length 1.5 m swings with a period of 3.3 s. What is the acceleration of gravity on this planet?

asked by Rachell on January 30, 2014
18. ## algebra

Give an example of an open equation? my answer is, x + 4 = 7 Until the value of x is found, it is unknown whether the equation is true or false. am i right?

asked by Jojo on November 6, 2017
19. ## math

solve for unknown: log9 r=3/2 logG 2=1/3 Can you show me the steps how to solve this problems.Thank yo very much for your time

asked by sandy on July 18, 2010
20. ## algebra

Give an example of an open equation? my answer is, x + 4 = 7 Until the value of x is found, it is unknown whether the equation is true or false. am i right?

asked by Jojo on November 6, 2017
21. ## Statistics

If, for a given sample size, 10% of all possible confidence intervals do not contain the unknown population parameter value, what is your confidence level?

asked by Anonymous on February 19, 2016
22. ## Algebra

Translate the sentence into an equation. The sum of a number times 6 and 8 is 7 . Use the variable b for the unknown number.

asked by Anonymous on July 31, 2017
23. ## Chemistry

what's the density of a cube of an unknown substance if mass is 45.2g and the side of a cube is 3.2cm?

asked by Nick on October 24, 2013
24. ## Science

An unknown substance has a volume of 25 mL. It is placed into a different container and its volume changes to 50 mL. What happened? Is it a change in state?

asked by Sebastian on January 29, 2013
25. ## Algebra1

Eight times the sum of 11 and a number is 123. Which equation can be used to find the unknown number?

asked by Keonsha on January 11, 2016
26. ## Chemistry

An unknown gas has a molecular weight of 30.07 g/mol. What is the density of the gas at STP?

asked by lauren on March 4, 2011
27. ## Math

What unknown number makes these equation true. 447+99 =447+100-

asked by Alyssa on October 5, 2016
28. ## Algebra

−20 times a number minus 36 is equal to -45 less than a number unknown is x write equation.

asked by Amber on February 4, 2017
29. ## chemistry

A solution containing 26.05 mg of an unknown protein per 23.5 mL solution was found to have an osmotic pressure of 3.75 torr at 44 C.

asked by M on January 25, 2010
30. ## chemistry

You measure the pH of a 0.50 M unknown acid solution using a pH meter and it is found to be 1.74. What is Ka for the acid? I know ph=-log{H+} Where do I go from here?

asked by anon on March 31, 2015
31. ## Chemistry

A sample of unknown ore was analyzed and fgound to contain 12.7% Al, 19.7% N,and 67.6% O. What is the empirical formula of this ore?

asked by Becca on December 8, 2010
32. ## science

an unknown metal has a volume of 20cm^3 and a mass of 54g. Identify the metal

asked by Matthew on April 11, 2010
33. ## Math

Translate into an equation use x to represent an unknown number two thirds of a number is negative 28

asked by Atavia on July 27, 2016
34. ## Science

Someone gives you an unknown mineral. You can scratch it with quartz but not with feldspar. What is the mineral's approximate hardness?

asked by Shamaree on April 20, 2010
35. ## Chem

the formula mass of an unknown compound is 44.009 amu. What is its molar mass?

asked by Mia on January 11, 2016
36. ## algebra 1

Eight times the sum of 11 and a number is 123. Which equation below can be used to find the unknown number?

asked by Alex on March 17, 2014
37. ## chemistry

A 4.50e-2 M solution of unknown monoprotic weak base has a pH of 10.200 what is the value of kb for the base

asked by Nancy on April 28, 2010
38. ## Science--HELP!!

1. In which of the following situations is a sound wave most likely to travel through air? A) An alarm clock rings in a vacuum. B) A giant star explodes. C) A grasshopper eats a leaf. D) An astronaut uses tools in space. 2. Which of the following factors

asked by Jasmine on December 9, 2013
39. ## Chemistry

A 12 g sample of an unknown compound contains 3.489 g of sodium and 4.870 g of sulfur. The rest is oxygen. Name the compound Thank you!

asked by Mom on October 17, 2011
40. ## Chemistry (Concentratrion/molarity)

A 25.00 mL aliquot of HCl of unknown concentration is titrated with 25.62 mL of 0.1011 M NaOH. What is the molarity of the HCl solution?

asked by Ray on November 1, 2016
41. ## Chemistry

It takes 49.0J to raise the temperature of an 8.80g piece of unknown metal from 13.0∘C to 24.7∘C. What is the specific heat for the metal?

asked by Annale on November 3, 2014
42. ## Chemistry

Suppose that 16.41 mL of 0.0512 M NaOH were required to titrate a sample of unknown acid. How many moles of NaOH were used?

asked by Erin on February 8, 2017
43. ## Algebra

Write an algebraic expression for the quantity. Let x represent the unknown value. Seven times a quantity decreased by thirteen

asked by Matt on April 7, 2016
44. ## Chemistry

Carborundum (silicon carbide) boiling chips are better than calcium carbonate chips in the recrystallization of an unknown,why ?

asked by david on September 20, 2012
45. ## Chemistry

Carborundum (silicon carbide) boiling chips are better than calcium carbonate chips in the recrystallization of an unknown,why ?

asked by david on September 20, 2012
46. ## BioChem

If you run an unknown sample and it is darker than your highest standard on your standard curve, what do you report as the concentration?

asked by Dreamland11 on October 31, 2011
47. ## chem

A 0.0097561 g quantity of an unknown gas occupies 0.2 L at 500 K and 2 atm. What is the Molecular Weight (MW) of the gas ?

asked by laura on December 5, 2011
48. ## chem

A 0.0097561 g quantity of an unknown gas occupies 0.2 L at 500 K and 2 atm. What is the Molecular Weight (MW) of the gas ?

asked by laura on December 5, 2011
49. ## math

problem is solve for the unknown 2/3 over 10 = 1.8 over r dont even know where to start to solve this please help cross-muliply 2/3 r = 18 multiply both sides by 3/2 thank you

50. ## chemistry

20.70 ml of .42 M HClO4 is required to neutralize .966g of an unknown base. Find the molar mass of the base .

asked by Cristina on May 7, 2014
51. ## Math

Use your new conjectures to arrange the unknown measures in order from greatest to least. Measures 5cm,9cm and 12cm

asked by Tahzh on November 11, 2011
52. ## calculus

help needed!!! how would you go about drawing the graph of a functions derivative, if the original function is unknown. IE only the graph if F(x) is given but not the equation. thanks

asked by Anonymous on July 21, 2009
53. ## Chemisrty 1

If ou knew the density of an unknown metal, do you think you could accurately determine the identity of the metal based on that property?

asked by Mariah on October 4, 2010
54. ## Chemistry

An unknown solution may contain one of the ions of the pair below. Devise a test which allows you to distinguish between the ions. Cu2+(aq) and Co2+ (aq)

asked by Charlie on November 29, 2012
55. ## Chemistry

What are the typical ppm values of hard water and an unknown water sample and how do their titrations compare?

asked by Jacob on March 12, 2014
56. ## Chemistry

Suppose that 14.9 mL of 0.0512 M NaOH were required to titrate a sample of unknown acid. How many moles of NaOH were used?

asked by Rae on March 5, 2014
57. ## statistics

12. The probability that the Dow Jones stock index will close above 18000 at the end of the year is an example of (a) classical probability. (b) subjective probability. (c) independent probability. (d) priory probability. 13. The probability calculated

asked by meri on June 30, 2015
58. ## Physics

I have two I need help with! 1. An airplane is flying in a horizontal flight level at constant velocity, heading due east. If the weight of the plane is 2.6 x 10^4 N, what is the net force on the plane? a)-2.6x10^4 N b)2.6x10^4 N c)0.0 N d) that due to

asked by Johnny on September 5, 2010
59. ## statistics

Use the data given in table 13.1 on page 846 to construct a frequency distribution with a first class ( in ten thousands ) of 150-296.

asked by Charles on January 2, 2012
60. ## physics

In a gas two waves of length 1m and 1.10m have a frequency difference of 10/3 Hz, the velocity of sound is ? a) 166m/s b) 332m/s c) 83m/s d) 336.7m/s

61. ## physics

Two sinusoidal waves of the same frequency travel in the same direction along a string. If ym1 = 4.2 cm, ym2 = 5.9 cm, ö1 = 0, and ö2 = /5 rad, what is the amplitude (in cm) of the resultant wave?

asked by mounir on December 20, 2010
62. ## Chemistry

If the activation energy for a given compound is found to be 42.0 kJ/mol, with a frequency factor of 8.0 × 1010 s-1, what is the rate constant for this reaction at 298 K?

asked by Kelsei on April 2, 2014
63. ## physics

A piano tuner hears one beat every 2.8 s when trying to adjust two strings, one of which is sounding 440 Hz, so that they sound the same tone. How far off in frequency is the other string?

asked by DJ on February 10, 2010

What is the frequency of a photon with a wavelength of 2.50 102 nm? (The speed of light in a vacuum is 2.998 108 m/s. Planck's constant is 6.626 10-34 J · s.

asked by mary on October 21, 2010
65. ## physicss

an. Electron travels in a circular orbit of radius 0.5 a and frequency of 5.5*10^7hz. Findthe magnetic field produced At center

asked by A on April 27, 2011
66. ## Astronomy

Calculate the wavelength and frequency of the radiation emitted by the electronic transition from the 10th to the 9th excited state of hydrogen.

asked by Anonymous on September 7, 2011
67. ## Math Ms.Sue Help

Which data value has the highest frequency? A) 1/16 B) 3/16 C) 3/8 D) 5/8 A number line with four x's above one sixteenth, one x above three sixteenths, one x above three eighths, two x's above one half, two x's above five eighth, and one x above three

asked by Selena on March 21, 2017
68. ## SCIENCE helppp!!

Our sun is what scientists call a "yellow-green star." Does it emit energy in the frequency of red light? I have no idea!

asked by Anonymous on January 6, 2010
69. ## Oscillations

The E string of a violin has a linear density of 0.5 g / m and is subjected to a 80N of tension, tuned for a frequency = 660 Hz a) What is the length of the rope?

asked by Vinicius on April 27, 2014
70. ## science

How long would it take a radio wave with a frequency of 5.1 × 105 Hz to travel from Mars to Earth if the distance between the two planets is approximately 8.00 × 107 km?

asked by Anonymous on November 4, 2012
71. ## physics

Two sinusoidal waves of the same frequency travel in the same direction along a string. If ym1 = 4.2 cm, ym2 = 5.9 cm, ö1 = 0, and ö2 = /5 rad, what is the amplitude (in cm) of the resultant wave?

asked by mounir on December 18, 2010
72. ## algebra

One can make predictions for certain events based on a) scientific evidence b) newspaper stories c) frequency of occurence d) personal observation Thank you!!!

asked by Philine on September 12, 2009
73. ## physics

how the frequency of the sound produced will change in the case of aluminium sting of length 15cm when the string is tied between two ends

asked by lakshya on July 2, 2011
74. ## physicss

an. Electron travels in a circular orbit of radius 0.5 a and frequency of 5.5*10^7hz. Findthe magnetic field produced At center

asked by A on April 27, 2011
75. ## Chemistry

Sodium vapor lamps are often used in residential street lighting. They give off yellow light with a frequency of about 5.91 × 1014 Hz. What is this wavelength in nm?

asked by Heather on November 20, 2013
76. ## chemistry

if the activation energy for a given compound is found to be 10 kJ/mol, with a frequency factor of 4.0x10^13 s-1, what is the rate constant for this reaction at 398K?

asked by hall on February 26, 2012
77. ## Physics

Two loudspeakers are 2.42 m apart. A person stands 3.42 m from one speaker and 2.82 m from the other. What is the lowest frequency at which destructive interference (sound cancellation) will occur at this point?

asked by Anonymous on March 4, 2011
78. ## chemistry

determine the end (final) value of n in a hydrogen atom transition, if the electron starts in n=2 and absorbs a photon of light with a frequency of 4.57 x 10^14 Hz.

79. ## physics

A electric model train travels at 0.339 m/s around a circular track of radius 1.75 m. How many revolutions does it perform per second, i.e, what is the motion's frequency?

asked by thuy on March 14, 2013
80. ## science

The equation y=5sin(3x-4) where y is in millimeters,x is in metres and t in seconds,represent motion. Find; Frequency Period Speed of the wave

81. ## physics

What's the shortest air column , closed at one end, that will resonate at a frequency of 440.0Hz when the speed of sound is 352 m/s

asked by Melissa on June 5, 2012
82. ## Physics

What is the wavelength of a radar signal that has a frequency of 30 GHz? The speed of light is 3 × 10^8 m/s. Answer in units of m Giving me the formula is just fine

asked by angel on April 1, 2012
83. ## Physics

What is the ratio of the wavelength of visible light of wavelength600 nm to that of an FM radio wave of frequency 100 MHz? c = 2.998x 108 m/s

asked by Amy on December 4, 2012
84. ## chemistry

how long would it take a radio wave with a frequency of 7.25 x 10to the 5th to travel from Mars to earth if the distance is approx. 8.0 x 10 to the 7th?

asked by karen on October 26, 2011
85. ## music

How does frequency, amplitude, and wave shape affect the pitch, intensity, and quality of notes produced by musical instruments.

asked by Sue on April 24, 2008
86. ## physics

Two loudspeakers are 2.54 m apart. A person stands 3.04 m from one speaker and 3.50 m from the other. What is the lowest frequency at which destructive interference (sound cancellation) will occur at this point?

asked by Student in Need on March 3, 2011
87. ## Chemistry

What is the frequency of the photons emitted by the hydrogen atoms when they undergo transitions from n=5 to n=3? In which region of the electromagnetic spectrum does this radiation occur?

asked by Anonymous on October 22, 2011
88. ## Chemistry

How would I find the collision frequency factor with this information? Slope- -8111.4 EA- 74089.36 j/mol y-int 24.897 1/T .003

asked by Matt on February 25, 2014
89. ## physicss

A child sits on a swing supported by ropes of length 3.0 m. With what frequency will she need to apply the driving force to maintain swinging?

90. ## Physics

A ceiling fan of radius 1.0 m is rotating with a frequency of 300 RPM. How fast (in m/sec) is the tip of one of the blades moving?

asked by Anonymous on December 8, 2015
91. ## physics

A electric model train travels at 0.339 m/s around a circular track of radius 1.75 m. How many revolutions does it perform per second, i.e, what is the motion's frequency?

asked by thuy on March 14, 2013
92. ## trig

The function d=-8cos2t describes a simple harmonic motion, where d is the distance(in meters) an object travel in t seconds. What is the frequency?

asked by rachel on April 13, 2010
93. ## applied maths

Partv1-v2cle A and B have masses 0.75 and 0.65 respectively. They are approaching each other moving along a straight line with speed 6m/s and 4m/s respectively. The coefficient between them is 4/3. After collision,the direction of motion of B is reversed.

asked by yhakubu on November 25, 2016
94. ## Chemistry

A .682 g sample of an unknown weak monoprotic acid, HA, was dissolved in sufficient water to make 50mL of solution and was titrated with a .135 M NaOH solution. After the addition of 10.6mL of base, a pH of 5.65 was recorded. The equivalence point was

asked by Sara on May 9, 2007
95. ## PHYSICS

Not sure how to set this one up. An object of unknown mass receives a 25 Newton force and accelerates at a rate of 0.55 m/s^2. What is its mass in kilograms?

asked by GRISSELL on February 4, 2012
96. ## physics

A Physics book , mass unknown , is dropped from a table . its velocity just before hitting the ground is 9.39 m/s . what is the height of the table ?

asked by bob on February 6, 2012
97. ## Physics

A 500-mL beaker has a mass of 250 g when empty and 645 g when filled with an unknown liquid. What is the density of the liquid?

asked by Lance on May 2, 2018
98. ## chemistry

what is the molar mass of the unknown gas that diffuses 0.250 times as fast as hydrogen gas under the same circumstances?

asked by Aamna Qamar on August 9, 2011
99. ## Thermochemistry

It takes 45.0 J to raise the temperature of an 9.70 g piece of unknown metal from 13.0 degrees C to 24.5 degreesC. What is the specific heat for the metal?

asked by Michelle on October 17, 2010
100. ## math

find the unknown lenght of a rectagular prism. Lenght=15 volume=180 ft square with= 4 ft my answer is x=120

asked by siulanis perez on June 16, 2015