Popular questions and responses by Liz
  1. Physics

    I was wondering if my answers are correct. Thanks in advance. 1. A boy pushes down on a car rolling horizontally down the road. The boy pushes down vertically with 10N of force as the car rolls 3.0m horizontally. What work is done? my answer: 30 N•m (or

    asked on February 3, 2014
  2. Physics

    I was wondering if my answers are correct. 1. A 50kg person is taking a ride on an elevator travelling up at a steady speed of 2.5m/s. Find the time fo the elevator trip if the elevator does 4900 J of work on the person. My answer: First I used the formula

    asked on February 3, 2014
  3. Physics- check answer please

    1. A 15 kg boy falls out of his bed at a height of 0.50 m. What is the amount of gravitational potential energy lost by the boy? my answer: 74 J 2. What is the speed of a 0.25 kg ball if its kinetic energy is 15 J? my answer: 11 m/s 3. if the speed of an

    asked on July 4, 2014
  4. Trigonometry

    A communications tower is located at the top of a steep hill, as shown. The angle of inclination of the hill is 58°. A guy wire is to be attached to the top of the tower and to the ground, 50 m downhill from the base of the tower. The angle α in the

    asked on October 1, 2014
  5. Physics waves- check answers please

    1. If a bat emits 10 sounds in 5 seconds, what is the frequency of the bat's vocal outbursts (rounded to first decimal place) My answer: 2.0 Hz 2.If one crest has a 3 cm amplitude and interacts with another pulse to produce a crest 8 cm high this

    asked on April 20, 2014
  6. Physics waves

    thanks in advanced! A guitar emits a 440 Hz tone. How far apart are the crests in room temperature air (20 degrees celsius)? How long does it take the string to vibrate from crest position to trough position (across twice the amplitude)?

    asked on April 22, 2014
  7. Physics waves- help please

    1. A person is listening to a new instrument capable of sounds ranging from 10 dB to 150 dB and with frequencies from 12 Hz to 30,000 Hz. Comment on the suitability of this instrument for the musician or audience. 2. A guitar emits a 440 Hz tone. How far

    asked on April 21, 2014
  8. Physics -- check answers please

    Use g=10 N/kg in this assignment. 1. What is the gravitational energy (relative to the unstretched surface of the trampoline) of the 20 kg ball at its apex 2 m above the trampoline? I got 400 J 2. What is the kinetic energy of the ball just before

    asked on July 3, 2014
  9. Physics waves- check answers please

    I am not too sure if my answers are correct. Here are the questions: 1. A student standing near a brick wall claps her hands and hears the echo 0.250 s later. If the speed of sound was 340.0 m/s, how far from the wall was she? For this question I got 85 m.

    asked on April 21, 2014
  10. word problem

    If equal amounts of heat are added to equal masses of silver and copper, both at the same initial temperature, which will reach the higher final temperature? Explain your answer. The specific heat capacity of silver is 0.235 J/g degree Celsius and that of

    asked on April 12, 2014

    An internal explosion breaks an object, initially at rest, into two pieces. One piece (m1) is 1.5 times more massive than the other (m2). If 7500 J were released by the explosion, how much KE did each piece acquire?

    asked on October 22, 2014
  12. physics - conceptual

    Three identical capacitors are connected in series to a battery. If a total charge of Q flows from the battery, how much charge does each capacitor carry? A)9Q B)Q/3 C)Q D)3Q E)Q/9

    asked on February 3, 2013
  13. physics

    How would I answer number 3? 1. A sumo wrestler originally jumps 10 cm above a trampoline but has the same total energy of a small ball that was 200 cm higher than the trampoline. What causes this equivalency? 2. If a 40 kg gymnast and a 400 kg sumo

    asked on July 3, 2014
  14. free-body diagram help

    A 20.0 kg block is being pushed forward on a flat surface with a force of magnitude 45.0 N against a frictional force of 13.0 N To draw this free-body diagram, would I only have the forces mentioned in the question? or would i include the -9.8m/s^2 force

    asked on April 13, 2014
  15. Physics waves- check answer please

    I would like to know if my answer is correct. Thanks in advanced! A person with their head sideways in the water sees a beaver slap its tail on the lake surface 1.2 km away. What is the time difference between the sound heard in the ear listening in the

    asked on April 22, 2014
  16. Business Math

    Joyce took out a loan for $21,900 at 12 percent on March 18, 2000, which will be due on January 9, 2001. using ordinary interest, Joyce will pay back on January 9 a total amount of: Answer: $24,068.10 Ordinary interest is 360 March 18 = 77 days January 9 -

    asked on January 29, 2012
  17. Physics waves- check answers please

    1. In a standing wave, the medium at the tip of a loop is a) showing destructive interference b) not moving c) at the original amplitude of the wave d) showing constructive interference my answer: b 2. If a motorcycle is travelling toward an observer the

    asked on April 21, 2014
  18. physics

    A baseball is tossed at a steep angle into the air and makes a smooth parabolic path. Its time in the air is t and it reaches a maximum height h. Assume that air resistance is negligible. a.) Show that the height reached by the ball is gt2 (square) /8. b.)

    asked on March 30, 2012
  19. Energy question

    How would a $10.00 compact fluorescent light bulb (15 W) be an overall money saver compared to an incandescent light bulb (60 W) that costs $0.50?

    asked on April 12, 2014
  20. Physics

    1. The weight in the following diagram has a mass of 0.750 kg and the cart has a mass of 0.52 kg. There is a friction force of 2.1 N acting on the cart. What is the tension in the string? a. 4.4 N b. 4.3 N c. 4.1 N d. 4.2 N 2. An 8.5 kg block is attached

    asked on June 2, 2017
  21. Math

    A local Dunkin donuts makes blueberry muffins that cost $.69 each to make. Past experience shows that 15% of the muffins will spoil and have to be discarded. Assuming this donut shop wants a 30% markup based on cost and produces 200 muffins, each muffin

    asked on January 19, 2012
  22. Physics -conceptual

    A 1 mF, a 2 mF, and a 3 mF capacitor are connected in series, the combination being connected across a 9 volt battery. Which capacitor has the greatest voltage?

    asked on February 3, 2013
  23. physics

    A large truck with a mass of 3200 kg is pulling a trailer with a mass of 2400 kg. Both are accelerating at a rate of 0.45 m/s^2 . Determine the tension force between the truck and the trailer, and determine the force with which the truck is pulling. I'm

    asked on June 2, 2017
  24. Physics -- check answers please

    I am to fill in the blanks without a word bank, my answers are in brackets. 1. A ____ diffraction pattern is unique because it has a larger central maximum. (single slit) 2. the brightest, clearest diffraction pattern is created with a _____ (barrier)

    asked on July 26, 2014
  25. Energy question

    Your friend comes across a good deal to purchase a gold ring. She asks you for advice for you to test the ring. The ring has a mass of 4.54 g. When you heat the ring with 94.8 J of energy, its temperature rises from 23.0 degrees celsius to 47.5 degrees

    asked on April 12, 2014
  26. Energy multiple choice question

    Which of the following samples has the highest specific heat capacity? a) A 100 kg sample of lead requires 13 000 J to increase its temperature by 1 K b) A 50 g sample of water releases 1050 J as it cools by 5 degree Celsius c) A 2 kg sample of copper

    asked on April 12, 2014
  27. 8th grade math

    if a person is 6 feet tall and casts a 9 foot shadow, how tall would the shadow of a 100 foot tall tree be?

    asked on December 4, 2011


    asked on October 16, 2009
  29. Physics -- check answers please

    The earth's magnetic field a) is slightly off centre compared to the Earth's rotational axis of rotation b) has its magnetic south pole at the geographic north pole c) attracts the north end of the compass needle to the geographic north pole d) all of the

    asked on May 21, 2014
  30. Math

    A wooden duck with a regular selling price of $125.99 is marked down to $79.99. The percent of markdown is: Answer: 36.51% What is the formula? How to solve this?

    asked on January 19, 2012
  31. physics

    Fill in blank Increasing the distance between a pair of slits through which light is being shone would ___ the distance between nodal lines appearing on a screen

    asked on July 27, 2014
  32. calc

    Nutrition Ruff, Inc. makes dog food out of chicken and grain. Chicken has 10 grams of protein and 5 grams of fat per ounce, and grain has 2 grams of protein and 2 grams of fat per ounce. A bag of dog food must contain at least 224 grams of protein and at

    asked on September 16, 2011
  33. Jewelry

    Found a gold ring engraved with cop 91© 8 on it, what does this mean? And is there any worth to it

    asked on August 29, 2018
  34. Physics waves- help please

    A police officer with good ears hears an approaching motorcycle. The engine sound he eats as the bike approached is 195 Hz. a) Is the actual sound the bike makes higher or lower in pitch? b) After the bike passes he hears 147 Hz as the perceived pitch. If

    asked on April 22, 2014
  35. Physics

    A ball is fastened to one end of a 30cm string, and the other end is held fixed to a support. the ball whirls in a horizontal circle. Find the speed of the ball in its circular path if the string makes an angle of 30 degrees to the vertical.

    asked on February 27, 2014
  36. Chemistry II

    Arrange the following 0.10M solutions in order of increasing pH: a. Nacl b. NH4CL C. HCL D. NaCH3CO2 e. KOH

    asked on April 30, 2013
  37. Physics

    A vibrating point on a spring travels 60 mm during three cycles. What is the amplitude of the vibration?

    asked on May 4, 2014
  38. statistics

    A student was asked to compute the mean and standard deviation for the following sample of n _ 5 scores: 81, 87, 89, 86, and 87. To simplify the arithmetic, the student first subtracted 80 points from each score to obtain a new sample consisting of 1, 7,

    asked on June 22, 2011
  39. math

    Obtain exponential functions in the form f(t) = Aert, if f(t) is the value after t years of a $9,000 investment depreciating continuously at an annual rate of 8.5%. f(t) = 1

    asked on October 7, 2010
  40. physics

    1. The weight in the following diagram has a mass of 0.750 kg and the cart has a mass of 0.52 kg. There is a friction force of 2.1 N acting on the cart. What is the tension in the string? a. 4.4 N b. 4.3 N c. 4.1 N d. 4.2 N 2. An 8.5 kg block is attached

    asked on June 2, 2017
  41. Physics- help please

    A beta particle (fast moving electron) is released by a nuclear decay and starts travelling at 1.5x10^6 m/s [NΘE] in the Earth's magnetic field which has a value of 3.0x10^-5 T. If the force experienced by the beta particle is 4.34x10^-18 N, determine the

    asked on July 10, 2014
  42. algebra 1

    find the common ratio of each sequence: 1. 8,20,50,125......? 2. 0.48,0.9,1.8,3.6.....?

    asked on March 31, 2009
  43. Physics help

    1. if the magnetic field is 2.1 m from a current carrying wire is 7.1x10^-5 T, what is the current flowing through the wire? 2. The electromagnet in an MRI has a magnetic field of 2.5 T. If there are 100 A of current running through the magnet, how many

    asked on July 9, 2014
  44. physics- answers check

    5. A magnetic field map shows a. the direction of the magnetic field. b. a few representational field lines. c. relative strength of the magnetic field. d. All of these choices are correct. my answer: d 6. Magnetic field lines a. can cross each other when

    asked on May 10, 2014
  45. Calc II

    A worker on scaffolding 65 ft above the ground needs to lift a 390 lb bucket of cement from the ground to a point 20 feet above the ground by pulling on a rope weighing 5 lb/ft. How much work is required?

    asked on October 16, 2012
  46. Algebra 2

    According to a survey conducted in 1990 by Independent Sector, the percent of their incomes that Americans give to charities is related to their household incomes. For families with annual incomes between $5000 and $100,000, the percent is modeled by P =

    asked on February 9, 2018
  47. Physics

    fill in the blank ( Energy and momentum unit) 1. the work done to stretch a spring is not equal to the to force multiplied by displacement because force is ____ as the spring stretches 2. A child goes down a slide at the playground, gaining speed as she

    asked on July 3, 2014
  48. chemistry

    If 5.30mL of 0.1000 M NaOH solution is needed to just neutralize excess acid after 20.00 mL of 0.1000 M HCl was added to 1.00 g of an antacid, how many moles of acid can the antacid counteract per gram?

    asked on March 3, 2013
  49. MATH

    The Megabuck Hospital Corp. is to build a state-subsidized nursing home catering to homeless patients as well as high-income patients. State regulations require that every subsidized nursing home must house a minimum of 770 homeless patients and no more

    asked on January 28, 2011
  50. Energy question

    how could you determine the efficiency with which the mechanical energy of a pendulum is conserved?

    asked on April 12, 2014
  51. Physics...PLZ!! =)

    A conducting rod whose length is 25 cm is placed on a U-shaped metal wire that has a resistance R of 8 Ù. The wire and the rod are in the plane of the paper. A constant magnetic field of strength 0.4 T is applied perpendicular and into the paper. An

    asked on March 12, 2013
  52. physical science

    What is the kinetic energy of a 29 kg dog that is running at a speed of 8.8 m/s (about 20 mi/h)?

    asked on September 9, 2012
  53. History

    Which factor contributed most to Florida becoming a U.S. territory? a. the outcome of the Seminole Wars b. the weakening of Spain's hold over its colonial possessions c. the desire of Southern politicians to expand slavery into new territories d. the

    asked on May 28, 2016
  54. Statistics

    The Boeing 757-200 ER airliner carries 200 passengers and has doors with a height of 72 inches. Heights of men are normally distributed with a mean of 69 inches and a standard deviation of 2.8 inches. b) assume that half of the 200 passengers are men, what

    asked on April 8, 2013
  55. Physics- check answer please

    1. A vibrating point on a spring travels 60 mm during three cycles. What is the amplitude of the vibration? a) 0.05 mm b) 5.0 mm c) d) e) 180 mm my answer: I got 10 mm but it is not listed as an option

    asked on May 2, 2014
  56. Physics waves- check answers please

    1. In a standing wave, the medium at the tip of a loop is a) showing destructive interference b) not moving c) at the original amplitude of the wave d) showing constructive interference my answer: b 2. If a motorcycle is travelling toward an observer the

    asked on April 21, 2014
  57. chemistry

    Sodium metal adopts a body-centered cubic structure with a density of 0.97g/cm3. A. Use this information and Avogadro's number to estimate the atomic radius of sodium. B. If it didn't react so vigorously, sodium could float on water. Use the answer from

    asked on April 3, 2014
  58. Math

    Bill furrier marks up mink coats 3000.00, which represents a 50% markup on cost. what is the cost of the coats?

    asked on January 19, 2012
  59. statistics

    A music industry researcher wants to estimate, with a 90% confidence level, the proportion of young urban people (ages 21 to 35 years) who go to at least 3 concerts a year. Previous studies show that 21% of those people (21 to 35 year olds) interviewed go

    asked on November 13, 2016
  60. Physics

    I am to fill in the blanks without a word bank, my answers are in brackets. 1. When light waves reflect from media in which the speed of light is slower, their phase (crest or trough) is ____ 2. The trick to being able to observe interference patterns for

    asked on July 26, 2014
  61. Precalculus

    A wheel rolling at a constant speed has a radius of 15 inches and takes 30 seconds to roll 100 feet along the ground. What is its angular velocity? Use 3.14 for pie, and solve to two decimal places.

    asked on February 22, 2012
  62. statistics

    In an extensive study involving thousands of British children, Arden and Plomin (2006) found significantly higher variance in the intelligence scores for males than for females. Following are hypothetical data, similar to the results obtained in the study.

    asked on June 22, 2011
  63. calculus

    Find the rate of change of area in respect to temperature of a rectangle. Its a steel plate that expands when heated. I have to find that rate of change when width is 1.7cm and length is 2.9. dl/dt=1.0 x 10^-5 (this is an exponent...) and dw/dt=8.0 x 10^-6

    asked on March 6, 2011
  64. Chemistry

    Metallic aluminum reacts with MnO2 at elevated temperatures to form manganese metal and aluminum oxide. A mixture of the two reactants is 67.2% mole percent Al. Find the theoretical yield (in grams) of manganese from the reaction of 240 g of this mixture.

    asked on October 8, 2009
  65. Math with science

    Radioactive iodine treatment is so successful at treating hyperthyroidism that it has virtually replaced thyroid surgery. To the nearest full day, determine how long it will take for 400 millicuries of I-131, which has a half-life of 8 days, to decay to

    asked on July 27, 2008
  66. chemistry

    how to calculate the amount of heat in calories absorbed when 50.0 g of water at 20 degrees C spreads over your skin and warms the body temperature, 37 degrees C

    asked on March 1, 2014
  67. algebra

    Factor the polynomial expression. If necessary, use the caret (^) to enter exponents. For example, write x2 as x^2.2x2 + 13x + 15

    asked on January 9, 2013
  68. chem

    A 5.00 liter sample of gas measured at 27.0*C and 1.25 atm presure has a mass of 10.13 g. What is the formula weight of the gas?

    asked on August 1, 2012
  69. english

    There are never enough discipline on the playground: someone always is getting hurt. Subject verb agreement.

    asked on June 26, 2012
  70. physics

    a 2.0kg object is pulled horizontally by a force of 6.3N along the floor where the coefficient of kinetic friction is o.24. what is the object acceleration

    asked on January 26, 2012
  71. physics

    in a 100m race, 2 sprinters finish at the same time of 10.2 seconds, accelerating uniformly, sprinter A took 2 seconds to obtain max speed, sprinter B took 3 seconds, they ran their max speed for the remainder of the race, what is the acceleration of each

    asked on January 17, 2012
  72. Algebra

    A student is taking a literature course in which four tests are given. To get a B, he must average at least 80 on the four tests. The student got scores of 82, 76, and 78 on the first three tests. Determine (in terms of inequality) what scores on the last

    asked on October 31, 2011
  73. PHYSICS ---HELP!

    A laser beam is directed at the Moon, 380,000 km from Earth. The beam diverges at an angle of 6.2×10−5 rad. What diameter spot will it make on the Moon? Express your answer using two significant figures.

    asked on October 18, 2010
  74. another rotation

    A hollow cylinder (hoop) is rolling on a horizontal surface at speed v = 1.85 m/s when it reaches a 23.5° incline.How far up the incline will it go? How long will it be on the incline before it arrives back at the bottom? Again, I am so confused about

    asked on March 11, 2010
  75. science chemistry

    if a 0.625g sample of magnesium chloride is dissolved in water and then precipitated with a silver nitrate solution,how many grams of silver chloride precipitate would be collected?

    asked on November 27, 2018
  76. Math

    Solve the equation on the interval [0, 2π). tan2x sin x = tan2x would it be 0, pi/2 ?

    asked on May 23, 2016
  77. chemistry

    How much heat energy, in kilojoules, is required to convert 37.0g of ice at −18.0 ∘C to water at 25.0 ∘C ?

    asked on May 9, 2015
  78. Chemistry

    I am to use this formula to find ΔH°f,methane: ΔH°comb=2ΔH°f,water+ΔH°f, carbon dioxide-ΔH°f,methane-2ΔH°f,oxygen For ΔH°comb, the value is 884 KJ/mol For ΔH°f,water, the value is -285.8 For ΔH°f,carbon dioxide, the value is -393.5 I was

    asked on July 20, 2014
  79. Physics

    1. What happens to the force required for an object to maintain circular motion if the period is halved (goes around twice as fast around the circle)? a) force doubles b) force quadruples c) force is halved d) force is quartered my answer: c 2. Which is

    asked on June 26, 2014
  80. physics- answers check

    1. For a bar magnet, the magnetic field lines point a. towards the South pole. b. towards the North pole. c. always towards the magnet. d. always away from the magnet. my answer: a 2. Magnetic field lines a. are straight lines. b. are always circles. c.

    asked on May 10, 2014
  81. chemistry

    a student determines the molar mass of methanol by the method used in this experiment. she found that the equilibrium temperature of a mixture of ice and pure water was .4 degrees Celsius on her thermometer. when she added 10g of her sample to the mixture,

    asked on May 22, 2012
  82. Calculus

    A container is in the shape of an inverted right circular cone has a radius of 2 in at the top and a height of 6 in. At the instant when the water in the conatiner is 5 in deep, the surface level is falling at the rate of -.4 in/s. Find the rate at which

    asked on May 17, 2012
  83. physics

    What pressure difference is required between the ends of a 2.0--long, 1.0--diameter horizontal tube for 40 water to flow through it at an average speed of 4.0 ? I know we have to find delta P, but i'm stuck on how to do that. Help would be great

    asked on April 12, 2011
  84. Math

    Is (0,2) a orderd pair a solution of 4x - 3y = 6? Explain.

    asked on February 7, 2011
  85. math

    Urban Community College is planning to offer courses in Finite Math, Applied Calculus, and Computer Methods. Each section of Finite Math has 40 students and earns the college $40,000 in revenue. Each section of Applied Calculus has 40 students and earns

    asked on October 16, 2010
  86. Math

    Adult tickets for a play cost $19 and child tickets cost $17. If there were 36 people at a performance and the theatre collected $646 from ticket sales, how many children attended the play?

    asked on December 7, 2009
  87. careers

    When John asked Melanie to babysit Saturday night, he told her that he would pay $7 per hour. She accepted and did the work but has not yet received the money. What type of contract was this? a. implied contract b. unilateral contract c. bilateral contract

    asked on April 19, 2017
  88. trigonometry

    The angles of elevation to an airplane from two points A and B on level ground are 50◦ and 67◦ , respectively. The points A and B are 3.9 miles apart, and the airplane is east of both points in the same vertical plane. Find the altitude of the plane.

    asked on January 11, 2017
  89. Math

    What is the 11th term of the following geometric sequence? Enter a whole number 7/9,-7/3,7,-21,63

    asked on August 1, 2015
  90. physics

    Would the answer be c? The electrical potential 10 cm from an electron is: a) 1.4x10^-8 V b) 1.4x10^-10 V c) 1.4x10^-7 V d) 1.2x10^-4 V

    asked on July 12, 2014
  91. Physics

    A 200-loop coil of cross sectional area 8.5 lies in the plane of the paper. Directed out of the plane of the paper is a magnetic field of 0.06 T. The field out of the paper decreases to 0.02 T in 12 milliseconds. (a) What is the magnitude of the change in

    asked on March 12, 2013
  92. Physics--PLZ HELP!

    When the switch is closed in a circuit, the wire between the poles of the horseshoe magnet deflects upward. From this you can conclude that the left end of the magnet is ---- -- -- -- -- -- -- A) a magnetic dipole. B) not contributing to the wire's

    asked on February 26, 2013
  93. Physics

    A parallel-plate capacitor is charged by a battery and then the battery is removed and a dielectric of constant K is used to fill the gap between the plates. Inserting the dielectric changes the energy stored by a factor of A)2. B)1/K. C)1 (no change).

    asked on February 3, 2013
  94. Calculus...plz help!!

    find dy/dx of xsiny-ycosx=1

    asked on October 7, 2012
  95. CALCULUS help! =)

    find the derivative of f(x)=3x^2-x using the limit definition.

    asked on October 7, 2012
  96. English (Check)

    Hi Teachers, will you please check my answers? 1. The speaker’s use of many exclamation points and imperative statements in “Beat! Beat! Drums!” helps readers feel the tone’s humor. urgency.

    asked on May 28, 2012
  97. Us History

    The Treaty of Versailles, explain what it was and why the United States refused to sign it. Predict how the missing signature of the United States might affect Europe in the future.

    asked on July 21, 2012
  98. math for the middle school and elementary teacher

    Which one of the following situations a permutation? a) the number of ways 10 people can be lined up in a line for basketball tickets. b) The number of possible four member bowling teams from a family of six siblings. c) The number of ways to choose a

    asked on February 28, 2012
  99. statistics

    SAT Exam Scores – A school administrator wonders if students whose first language is not English score differently on the math portion of the SAT exam than students whose first language is English. The mean SAT math score of students whose first language

    asked on October 7, 2011
  100. latin

    The most significant reason for the decline of the Latin Grammar School was that it:

    asked on May 5, 2011


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