Questions Asked on
January 24, 2015

  1. Physics

    A motorcycle is following a car that is traveling at constant speed on a straight highway. Initially, the car and the motorcycle are both traveling at the same speed of 19.0m/s , and the distance between them is 52.0m . After t1 = 5.00s , the motorcycle

    asked by Anonymous
  2. vet tech

    The ear is ___ to the eye? A.palmar B.rostral C.caudal D. Cranial. I put d but they said it's wrong so what else can it be?

    asked by cali
  3. socialstdies

    Which of the following was an advantage of the South at the beginning of the Civil War? (1 point) The South had agricultural products to provide food for the army. The South had many factories that created superior machinery. The South had a more advanced

    asked by XenaGonzalez
  4. social studies 8th

    1. What was an underlying source of tension in westward expansion during the 1850s? (1 point) the inflation of goods a sharp decrease in population whether newly added territories should allow slavery **** disagreement over whether the economy of new

    asked by TINA
  5. english

    Identify the sentence that is punctuated correctly. a Give me a call tomorrow, veronica, when you get home, so we can discuss the details of the upcoming event. b. Give me a call tomorrow, Veronica, when you get home so we can discuss the detail of the

    asked by Anonymous
  6. socialstdies

    What did the Union Army gain as a result of the Battle of Vicksburg? (1 point) The Union Army captured thousands of prisoners of war. The Union Army used Southern slaves as fresh recruits. The Union Army gained control of the Mississippi River. The Union

    asked by XenaGonzalez
  7. Geometry ques

    Find the area of the region bounded by C: y = tanx , tangent drawn at C at x = pie/4 and the x- axis.

    asked by Shanu
  8. pre-calculus

    The terminal ray of an angle passes through the point (5,12). What is the value of cosine for this angle?

    asked by Anonymous
  9. Chemistry

    Consider the titrtation of 25.0mL of 0.0100M Sn2+ by 0.0500M TI3+ in 1 M HCL, using Pt and Saturated Calomel Electrodes to find the endpoint. F=96486.7 Cmol E0 Sn4+/Sn2+ =0.15V E0 TI3+/TI+ = 1.28 Esce = 0.241V R=8.3141 J K Mol (D) calculate E at the

    asked by Sam
  10. Language artsssss

    Which sentence correctly uses a predicate pronoun as a subject complement? (1 point) The last arrivals were Joe and I. This year's soccer champions were Lana and me. The tribute deeply touched my brother and I. My boyfriend became my best friend. 8. Which

    asked by XenaGonzalez
  11. SOCIAL STDIES HELP!

    Select the effects of the Union blockade of the South. (Choose all that apply.) (2 points) Some individuals became blockade runners. It prevented access to Confederate ports. It stopped the manufacture of goods in Confederate states.**** It lessened the

    asked by XenaGonzalez
  12. Physics

    Two students on roller skates stand face-toface, then push each other away. One student has a mass of 96 kg and the second student 56 kg. Find the ratio of the magnitude of the first student’s velocity to the magnitude of the second student’s velocity.

    asked by Marie
  13. College Physics

    An electron in a television tube travels the 12 cm distance from the grid to the screen at an average speed of 7.00 107m/s. How long does the trip take?

    asked by John
  14. physical

    an orienteer runs 300m north and then 400m to the southeast (at a 45 degree angle to north). if he runs at a constant speed, how far away is he from the starting position?

    asked by tarkan
  15. statics

    in a certain normal distribution , 1.25% of the area lies to the left of 42 , and 1.25% of the area lies to the right of 48. find population mean and sigma

    asked by Anonymous
  16. algebra

    The line l_1 passes through the points (3,-3) and (-5,2). The line is the graph of the equation Ax + By = C, where A, B, and C are integers with greatest common divisor 1, and A is positive. Find A + B+ C.

    asked by Kevin
  17. Physics

    Three charges, Q1, Q2 and Q3 are located on a straight line. The charge Q3 is located 0.136 m to the right of Q2. The charges Q1 = 1.22 μC and Q2 = -2.46 μC are fixed at their positions, distance 0.301 m apart, and the charge Q3 = 3.03 μC could be moved

    asked by Anonymous
  18. math

    If 60 feet of uniform wire weighs 80 pounds, what is the weight of 2 yards of the same wire?

    asked by Irene Wu
  19. Static

    The country of Statland runs a national lottery for its people. In this lottery, an urn contains 42 balls that are individually numbered 1, 2, ..., 42. Each week, 5 balls are drawn from the urn without replacement. Gamblers pay a small sum to predict these

    asked by De
  20. physics

    an orienteer runs 300m north and then 400m to the southeast (at a 45 degree angle to north). if he runs at a constant speed, how far away is he from the starting position?

    asked by tarkan
  21. Pre Calculus

    Approximate, to the nearest 0.01 radian, all angles theta in the interval [0,2pi) that satisfy the equation. a.) sin theta=-0.0135 b.) cot theta=-2.731 Thank you for helping! I appreciate it!

    asked by Anonymous
  22. Physics

    A car slows down from a speed of 24.0m/s to rest in 9.0s, How far did it travel in that time?

    asked by David
  23. Math

    True or false and if false write a true statement 1. A right triangle has three right angles. 2. A triangle that has three sides of the same length is an equilateral triangle. 3. An obtuse triangle has two angles that are acute. 4. In a right triangle the

    asked by Randy
  24. statistics

    In a class of 300 students, John’s rank was 40. Find his percentile rank

    asked by Anonymous
  25. Physics

    A motorcycle is following a car that is traveling at constant speed on a straight highway. Initially, the car and the motorcycle are both traveling at the same speed of 19.0m/s , and the distance between them is 52.0m . After t1 = 5.00s , the motorcycle

    asked by Anonymous
  26. chemistry 116

    You have a rigid sealed container held at a constant temperature. You add 3.3 atm of oxygen gas, 1.7 atm of nitrogen and 4.2 atm of methane to it. What is the partial pressure of the oxygen gas in the container

    asked by ALEX GOLD
  27. financial accounts

    sandeep purchased a machinery for 21000 on 1 January 2001. the estimated life of the machine is 10 years after which its residual value will be 1000 only.find out the amount of depreciation and prepare machinery account for the first three years according

    asked by medi
  28. chemistry

    A sample of 10.00g of a solid unknown was dissolved in 25.00g of water. Assuming that pure water freezes at 0.0°C and the solution freezes at -5.58°C, what is the molal concentration of the solution? What is the molar mass of the solid? Show your

    asked by paula
  29. Physics

    Any help direction is appreciated. Inez is putting up decorations for her sister's quinceanera (fifteenth birthday party). She ties three light silk ribbons together to the top of a gateway and hangs from each ribbon a rubber balloon. To include the

    asked by Hanna
  30. chemistry 113

    The AM band of radio waves are measured in kilohertz (kHz), which are the numbers you see on the AM radio dial. Therefore, a radio station at 610 on the AM dial has a frequency of 610 kHz or 610,500 Hz. What is the wavelength of the radio station that has

    asked by ALEX GOLD
  31. history? help

    In this portfolio assignment, you have chosen an event from the Civil War or pre-war era, have taken notes on this event, and now will take on a persona from the event. For example, you could choose to portray a Union soldier at Gettysburg, a plantation

    asked by XenaGonzalez
  32. Math

    Suppose an object is dropped from a height h0 above the ground. Then its height after t seconds is given by h = −16t 2 + h0, where h is measured in feet. Use this information to solve the problem. A ball is dropped from the top of a building 59 ft tall.

    asked by G
  33. Math

    Atop 50m tower, Jack sees smoke in two areas. One is on a bearing of 40degrees with an angle of depression of 8degrees, and the other on a bearing of 205degrees with and angle of depression of 13degrees. How far apart are the smoke sources? I'm not sure

    asked by Abdul
  34. Chemistry

    What two factors influence the effectiveness of molecular collisions in producing chemical change?

    asked by Anonymous
  35. Math

    What simplified common fraction is equivalent to 0.05757575757

    asked by Scott
  36. College Physics

    Two pucks traveling at each other collide and deflect at 30.0° angles from their original velocities. The mass of Puck B is 20% greater than the mass of Puck A. Before colliding, the pucks approach each other with momenta of equal magnitudes and opposite

    asked by Bill Smithers
  37. chemistry 113

    How many grams of sodium sulfate do you need to create 750 mL of a 0.250 M solution of sodium sulfate

    asked by ALEX GOLD
  38. physics

    Tom has a mass of 67.2 kg and Sally has a mass of 58.5 kg. Tom and Sally are standing 23 m apart on a massless dance floor. Sally looks up and she sees Tom. She feels an attraction. If the attraction is gravitation, find its magnitude. Assume both can be

    asked by Andy
  39. physics

    One particle has a mass of 2.86 x 10-3 kg and a charge of +7.32 μC. A second particle has a mass of 6.41 x 10-3 kg and the same charge. The two particles are initially held in place and then released. The particles fly apart, and when the separation

    asked by S
  40. Geometry

    The surface of a cube is painted red and blue, 3 sides of each. The cube is cut into 27 equal sized smaller cubes. Find both answers to the question, "How many cubes have at least 2 sides painted blue?" and "How many cubes have at least 1 side painted

    asked by Susan
  41. home economics

    Please help me!,how is home economics related to mathematics,science and social,spiritual and moral education (ssme)?

    asked by sara
  42. chemistry help

    What are the differences in measuring the molar mass using freezing point depression between studying ionic solids and molecular solids?

    asked by paula
  43. Science

    For the dissociation of acetic acid, CH3COOH CH3COO- + H+, the free energy change, ΔG° = 27.26 kJ/mol. What is the free energy change, ΔG°', in the biochemical standard state? Given R = 8.315 J/mol · K. T = 25°C.

    asked by Laura
  44. math

    If p pencils cost d dollars, how many pencils can be bought for c cents?

    asked by Irene Wu
  45. Physics

    1) if a positive and negative charge each has a magnitude of 6 uC and are separated by a distance of 10 cm, what is the force between the particles? 2) Given that the repulsive force between two identical positive point charges is 1.0 N when the charges

    asked by Help!
  46. math

    A box with a square base and no top is to be made from a square piece of cardboard by cutting 4-in. squares from each corner and folding up the sides, as shown in the figure. The box is to hold 324 in3. How big a piece of cardboard is needed?

    asked by G
  47. Intro. Physics!!!

    1------- A -10 uC charge is placed 0.20 m away from an unknown charge. The force between the two charges is found to be attractive and has a value of 9.0 N. What is the magnitude and sign of the other charge? 2-------- A -5 uC charge is a distance of 12 cm

    asked by Anonymous
  48. chemistry

    Calculate the final temperature if 50 kg of iron is heated from 15.0°C with 5000 kJ of heat. The molar heat capacity of iron is 25.08 J mol–1 K–1.

    asked by Lisa
  49. science

    A tractor pulls a tree trunk across a horizontal piece of ground. If the force in a chain is 3000N and the chain forms an angle of 30 degrees with the ground, calculate the force with which the tree is pulled across the ground and the force with which the

    asked by Anonymous
  50. Social Studies

    2.)Why were Native Americans forced to leave their lands during the 1830s? a.)settlers wanted to settle the land b.)U.S. citizens settled the land first c.)the Supreme Court ordered their removal d.)their new lands were better for farming 4.)How did

    asked by Yvonne
  51. Chemisty Help

    using 1-bromobutane and any necessary organic or inorganic reagent, suggest efficient syntheses of each of the following alcohols: 1) 1-pentanol 2) 2-hexanol 3) 1-phenyl-1-hexanol 4) 3-methyl-3-heptanol 5) 1-butylcyclobutanol Thank you!

    asked by Anonymous
  52. physics

    A series of two 2.0 kg blocks are attached together through string B.Two of the blocks weigh each 2.0 kg and are now being use for a new experiment. The blocks are being pulled upwards by another string A with a force of 25 N. What is the acceleration of

    asked by Anonymous
  53. Physics

    In a 100 m linear accelerator, an electron is accelerated to 1.40% of the speed of light in 46.0 m before it coasts for 54.0 m to a target. What's the electron's acceleration during the first 46.0 m? b) How long does the total flight take?

    asked by Jay
  54. physics

    After coming down a steep hill at a constant speed of 49 m/s, a car travels along the circumference of a vertical circle of radius 329 m until it begins to climb another hill. What is the magnitude of the resultant force on the 170 kg driver of the car at

    asked by d
  55. physics

    Two stones are thrown simultaneously, one straight upward from the base of a cliff and the other straight downward from the top of the cliff. The height of the cliff is 6.82 m. The stones are thrown with the same speed of 8.88 m/s. Find the location (above

    asked by Syd
  56. Geometry, Cubes

    The surface of a cube is painted red and blue, 3 sides of each. The cube is cut into 27 equal sized smaller cubes. Find both answers to the question, "How many cubes have at least 2 sides painted blue?" and "How many cubes have at least 1 side painted

    asked by Cathy
  57. math

    At c cents per pound, what is the cost of a ounces of salami?

    asked by Irene Wu
  58. Physics

    car leaves skid mark 72m in length with a deceleration speed of 7.20m/s^2. what was the initial speed prior to braking?

    asked by David
  59. physics

    A series of two 2.0 kg blocks are attached together through string B.Two of the blocks weigh each 2.0 kg and are now being use for a new experiment. The blocks are being pulled upwards by another string A with a force of 25 N. What is the acceleration of

    asked by Anonymous
  60. Business Law

    To obtain a social security number you must complete a form and show evidence of where you were A. live B. where to school C. go to Church D. were born I chose D. Check my answer to make sure please? Because I was stuck between A ad D.

    asked by Tine
  61. Business Law

    Many wills are held to be void because they were drafted and signed by people who did not seek: A. Witness B. Relatives C. Legal Advice D. Agents. I chose A. Witness.

    asked by Tine
  62. physics

    A ball of mass 21.7 g is attached to a cord of length 0.61 m and rotates in a vertical circle. What is the minimum speed the ball must have at the top of the circle so the cord does not become slack? The acceleration of gravity is 9.8 m/s . Answer in units

    asked by d
  63. Math

    1. "A bacteria population doubles in number every 3 hours. If there are 40 individuals now, how many in 24 hours?" SO I used the geometric series sum formula, with n=8(24/3=8), t1=40, and r=2, but I got 10200 as the answer, instead of what the answer key

    asked by Bethany
  64. Geometry

    The surface of a cube is painted red and blue, 3 sides of each. The cube is cut into 27 equal sized smaller cubes. Find both answers to the question, "How many cubes have at least 2 sides painted blue?" and "How many cubes have at least 1 side painted

    asked by Cathy
  65. Algebra Rearrangement

    Please rearrange h=rx^2-tx to make x the subject.

    asked by Nick
  66. biology

    a biologist prepared a strip of agar (a gelatin- like substance) as shown in the figure below. at position 7, he placed a concentrated sample of amino acid A and at position 1, a concentrated sample of enzyme E. E is known to catalyze the conversion of A

    asked by stella
  67. chemistry 113

    What is the molar mass of iron(II) chloride tetrahydrate? The error interval is +/- 2 g/mol.

    asked by ALEX GOLD
  68. Math

    Hi! Can you check my answers to this worksheet? They're the only questions I'm not positive about my answers on. 1. Compared to its parent function, describe the transformation of the following: y = -x3 + 2 A. Reflected with respect to x-axis, moved up 2.

    asked by Krystal
  69. maths

    Radius of a circle inscribed in a regular hexagon is 24 c.m. then find the length of hexagon

    asked by sanjay
  70. Math

    Check my math please... is the probability of three events with the following individual probs: 1/161x10/100x20/100=0.00012; and that is a 0.012% (1.2%) chance? Thanks

    asked by charlie
  71. chemistry 116

    Old fashion steam locomotives operated by boiling water and using the steam to drive a piston that moved the train. How much energy ( in MJ) is required to turn 824 gallons of water at 100 C into steam? The heat of fusion for water is 6.01 kJ/mol and the

    asked by daniel miller
  72. Trignometery

    Kappy is looking up at a blue UFO hovering above a crop circle with an angle of elevation of 64°. The crop circle is 42m from Kappy. A larger, red UFO is hovering straight above Kappy, looking down at the blue UFO with an angle of depression of 12°. How

    asked by Shanu
  73. Maths

    If 15 swallows flew 380 miles south then had a rest,then flew 800 miles towards the coast. How many miles did each fly? How many miles they flew altogether?

    asked by Jim
  74. Math

    Cannon wants to make a garden with a border of his yard. He has lumber in several different lengths. Which three lengths could be used to make a right triangle to fit into the corner of his yard? A. 4ft.,6ft.,10ft. B.7ft.,12ft.,15ft. C.5ft.,12ft.,13.

    asked by Daisy
  75. Math

    Q1.A tree was chopped by the Samuels family for the holidays. How tall was the tree originally if the piece they chopped down was 7feet tall, and fell 4 feet from the stump? Q2. Mr pratt's rake is leaning up against a wall. If the top of the rake hits the

    asked by Daisy
  76. Math

    George is making a permanent for his favorite baseball team. He wants the short edge to be 14 inches and the height in the middle of the right triangle to be 24 inches. What is the length of diagonal side AB?

    asked by Daisy
  77. math

    A piece of fabric is cut into three sections so that the first is three times as long as the second and the second is three times as long as the third. What part of the entire piece is the smallest section?

    asked by Irene Wu
  78. law

    how they can determine whether or not the jury's decision was right or wrong. Does it come down to matter of opinion by the judge? Is it biased? How does that work with posttrial motions.

    asked by Kim
  79. chemistry 113

    What is the wavelength of light that has a frequency of 6.80E+14 Hz. Express the wavelength in nanometers

    asked by ALEX GOLD
  80. Chemistry (Chromatography)

    Comment on the order of elution of the following solutes in (a) normal-phase and (b) reversed-phase liquid chromatography. Give reasons for the difference. Solute X nonpolar Solute Y polar, a dipole Solute Z polar, more polar than Solute Y

    asked by Jacob
  81. statistics

    In throwing a pair of dice The event of getting a sum of 5 in the upturned faces of dice.

    asked by flor
  82. accounting,life science and history

    What course can I do in college o university and career job can I persue after I've got my degree

    asked by nokuthula molekoa
  83. math

    what are the next four of the sequence represented by the expression 3n+5?

    asked by Please Help
  84. linear algebra

    If A is an n × n matrix, then A = S + K, where S is symmetric and K is skew symmetric. Let A= [1 3 -2;4 2 2;5 1 2] Find the matrices S and K described above can some0ne explain how to get these two matricies? thanks

    asked by sam
  85. Social studies

    In Greece what were the first competitions other than sports in the Olympics

    asked by Anonymous
  86. psychlogical statistics

    A random selection of files from a student counseling center revealed the following reasons why college students seek services: Mental health issues - 25 Learning/school issues - 15 Relationship issues - 5 Other - 5 What is the probability that if we

    asked by theresa
  87. businessprogramming

    A cattle feed company has two grades of feed , A and B . Feed A cost $2 per 100 pounds and feed B cost $3 per 100 pounds . Ranchers can order a mixture of feeds A and B . Write a program that calculates the charge for a feed order . The program should ask

    asked by Marsha
  88. Algebra

    Identify the solutions of equations if any x+2y=7 6x-2y=7

    asked by Linda
  89. maths

    Radius of a circle inscribed in a regular hexagon is 24 c.m. then find the length of the side of hexagon

    asked by sanjay
  90. chemistry 116

    Chlorine is used to disinfect drink water supplies and pool water. Suppose you have 13.8 L of Cl2 in a cylinder at 1000 torr and 24 C. How many grams of chlorine do you have in the gas cylinder?

    asked by daniel miller
  91. chemistry 116

    Suppose someone had an excessive Friday evening drinking party and then did the ultra-dumb thing of driving home while drunk. Luckily, the person got pulled over by the police before they can injure anyone else. The police took a blood alcohol reading of

    asked by daniel miller
  92. Geometry

    P(2ap, ap^2) is a any point on the parabola x^2=4ay other than its vertex. The normal at P meets the parabola again at Q. Find the coordinates of Q.

    asked by Shanu
  93. Math .Static

    Consider two events A and B in the same sample space such that P(A)=0.4 and P(B)=0.3. Then A and B are mutually exclusive. True or False

    asked by denial
  94. Health

    Scenarios that requires a patient to be a person assist instead of one person during patient care and why? I already have someone paralyzed and that is badly injured? What are some more?

    asked by Jamie
  95. Mathematics

    A train travels 60 km at a constant speed of 40km per hour for 1.5 hours. Explain why the total distance traveled does not affect the speed.

    asked by Andre1
  96. maths triangels

    a building having height 25ft cast a shadow 35ft and a person standing on the building of height h and cast a shadow 10 ft wht is the height off man ? please answer me how to solve

    asked by jaspreet
  97. combination probability

    A bag contains 6 red, 7 white and 5 blue marbles, how many ways can four marbles be picked where there are an equal number of red and white marbles? Is it 315 ways?

    asked by mary
  98. math

    my sun in thea 1st grade me no understand to much english i need very much help what is 9+10=??? me having very hard time help asap

    asked by fgar
  99. Education/college

    I had to create some learning goals for a personal Finance course (I am pretending to teach. I have these learning goals that I need to make less ambiguous. Can you help me? Balance a checkbook Understanding the banking process Identify pros and cons of

    asked by Cathy
  100. Math

    how could you change one of the squares so that a right angle would be created

    asked by Daisy
  101. English

    I am currently writing an argumentative essay about religion. The question is; Does religion better us as a society or does it create more conflict and division in the world? Being the Devils Advocate that I am I am going to argue that it creates more

    asked by Briana
  102. Math

    Hi! Can someone help me with these? I just learned about them yesterday but I'm really confused. All my teacher wants me to do is solve each equation and that's all the directions she gave. Thanks so much! 1.) 3cot^2 x-1=0 Location on Unit Circle: Period:

    asked by Stephanie
  103. math

    Perimeter of rectangle and a square are equal. Perimeter of the square is 96 cm and breadth of the rectangle is 4 cm less than the side of the square. Then two times the area of the rectangle is

    asked by ARUN
  104. Trigonometry

    Law of Sines sigma=27 deg 30' c= 52.8 a=28.1 Please show two solutions (beta1, beta2,...) due to acute and obtuse angles. Thank you so much for helping!

    asked by Anonymous
  105. Concept development

    A lesson plan is important for a teacher because it helps the teacher A. make decisions about what to teach on a daily basis. B. formulate experiences that will aid in concept development. C. organize his or her thoughts. D. remember the students' names.

    asked by Daniella
  106. math

    if I save 3200 for 40 years with 9% interest rate how much will I have saved

    asked by mary
  107. concept development

    Free play, eating a snack, painting, hearing a story, and so forth are related to which of the following learning concepts? A. Space B. Classification C. Size D. Time my answer is d.

    asked by Daniella
  108. concept development

    Which of the following is not a reason to make mathematics and science instruction relevant? A. To protect schools from being sued for discrimination B. To consider diversity in race, ethnicity, social class, and gender C. To build on concepts that

    asked by Daniella
  109. MATH Fractions

    I have two marbles. 1/6is blue. How many marbles do I have

    asked by belange
  110. math

    2x2 + 8x + 3 = 0

    asked by ALEX GOLD
  111. math

    The quadratic equation frequently appears in both the equilibrium and acid-base sections of General Chemistry. Therefore, it is useful to refresh the use of the quadratic before applying it to chemistry questions. Which of the following answers is a viable

    asked by ALEX GOLD
  112. Algebra

    Let n! = 1 x 2 x 3 x 4 x ... x n for integer n >_1. What could be the value of 1! +(2 x 2!) + (3 x 3!) + (4 x 4!) + ... (10 x 10!)?

    asked by Shanu
  113. Algebra

    To prove: (1 + 2 + 4 + . . . + 2n) + 1 = 2n+1 , ?n = 0 by induction

    asked by Shanu
  114. Science

    Identify and discuss at least two forces that would be involved when an elderly patient who is proped up at about 4 degrees in a bed and slowly slides down to an almost horizontal position?

    asked by Ella
  115. Algebra tricky ques

    if w is one of the complex cube roots of unity, show that 1+w equals 1. w is raised to power 2

    asked by Shanu
  116. Set Question 1

    Simplify(X U Y U Z) n (X U (Y n Z))

    asked by Shanu
  117. Probability Ques

    what is the probability for getting four cards higher than 10 on one hand in whist.

    asked by Shanu
  118. Paarabola Ques

    what is the conditon fost. line y=mx+c to be normal to parabola y^2=4ax?

    asked by Shanu
  119. maths

    chnge engineering stress=34.67*10 rais to the power-6 peta newton/metersquare to atto lb/square miles?

    asked by jaspreet
  120. crime

    How might a news company’s political alignment alter its presentation of crime in America?

    asked by sam
  121. Geometry

    How many different surface areas are possible when 8 one inch cubes are arranged so that each has one or more faces in common (touching) with at least one of the other cubes? We have to use a physical model. And I have no idea how to start this or even do

    asked by Cathy