1. PHYSICS

    In the Bohr theory of the hydrogen atom, an electron moves in a circular orbit about a proton, where the radius of the orbit is approximately 0.542 multiplied by 10-10 m. (The actual value is 0.529 multiplied by 10-10 m.) (a) Find the electric force

    asked by smita on September 13, 2013
  2. physics

    The Earth’s radius is about 6380 km. The space shuttle is orbiting about 300.1 km above Earth’s surface. If the average speed of the space shuttle is 25700 km/h, find the time required for it to circle Earth. Answer in units of h

    asked by joselyne on September 29, 2011
  3. physics

    The average speed of an orbiting space shuttle is 20100 mi/h. The shuttle is orbiting about 196 mi above the Earth’s surface. Assume the Earth’s radius is 3963 mi. How long does it take to circle the Earth? Answer in units of h ( hours)

    asked by ashley on June 11, 2011
  4. Physics

    the hubble telescope has a mass of 1.5 x 10^4 kg and its orbiting the earth 596 km above the ground surface.the earths radius is 6.38 x 10^3km. CAlculate a)the force of gravitation on the telescope due to the earth's pull. given: G=6.67 x 10^-11Nm/kg and

    asked by johnny on October 29, 2007
  5. physics

    1. Measurements show that there is an electric field surrounding the Earth. Its magnitude is about 100 N/C at the Earth's surface and points inward toward the Earth's center. From this information, can you state whether the Earth is negative or positive?

    asked by Nicole on July 15, 2010
  6. Earth's Dynamic Atmosphere

    The Sun heats the Earth. The Earth then reradiates this heat energy back into space. However, the amount of _______ in the air plays a key role in absorbing much of this exiting heat and warming Earth's atmosphere. A. carbon dioxide B. nitrogen C. oxygen

    asked by Prisila on December 26, 2017
  7. physics

    A projectile with mass of 139 kg is launched straight up from the Earth's surface with an initial speed vi. What magnitude of vi enables the projectile to just reach a maximum height of 5.8RE, measured from the center of the Earth? Ignore air friction as

    asked by Ugandanmafia on February 28, 2011
  8. physics

    A de-orbit burn, similar to that presented in the previous math problem, has been performed. During this de-orbit burn a pre-calculated ∆V (delta V, change in velocity) of 290 ft/s (or 88.4 m/s) will be used to decrease the Shuttle’s altitude from 205

    asked by Levi B. on January 20, 2012
  9. English

    1. In which of the following selections is point of view used to highlight contradictions in what is being described? A) "Aztec Creation story" B) "Day of the Butterfly" C) "At the Tourist Centre in boston"** D) "Two Bodies" 2. Which of the following

    asked by Starcatcher on September 19, 2016
  10. physics/calculus

    I need help in calculating work. following quantites are given. * G: 6.67E-11 *Mass of earth:5.98E24 *mass of satelightt:80kg *x(initial) center of the earth-7E6 m *x(final) center of the earth 12E6 m How do I make integral equation I need use 20 interval.

    asked by jenny on April 7, 2014
  11. Geometry

    Earth has a radius of about 12,500 km. If the volume of the earth were to remain the same, but the shape of the earth was a cube, what would be the approximate length of one side of the cube? A.)12,500 km B.)15,240 km C.)20,150 km

    asked by kiki on July 14, 2012
  12. physics

    The mass of Earth can be calculated using the fact that the weight of an object (in newtons) is equal to the force of gravity between the object and Earth. Given that the radius of Earth is 6.4*10^6m , determine its mass

    asked by Melissa on April 2, 2012
  13. physics

    a space probe launched from earth and orbits at a distance of 15,000 m from earth's center, the gravitational force is 500 N. What is the size of force when it is 25,000 m from earth.

    asked by Bill on November 5, 2013
  14. trig

    A space shuttle 200 miles above the earth is orbiting the. Earth once every 6 hours. how far does the shuttle travel in one hour? Note the radius of earth about 4000 miles.

    asked by Ali on September 18, 2011
  15. English

    I forgot to include the following sentences. 1) I hate people zapping (channel surfing, channel-hopping) when watching TV. 2)We bought a Freeview box an a satellite dish to watch (free) satellite channels around the world. 3) We also subscribed (?) to Sky

    asked by Mike on March 10, 2011
  16. Physics

    A spaceship of mass m travels from the Earth to the Moon along a line that passes through the center of the Earth and the center of the Moon. (a) At what distance from the center of the Earth is the force due to the Earth five times the magnitude of the

    asked by jawn on October 6, 2009
  17. Math

    Can You help me with this question? The distance from the earth to the sun is about 1.5 X 10^8 km, while the distance from the earth to the moon is about 3.8 X 10^5 km. If a scale model of the solar system is constructed so that the distance from the Earth

    asked by Sam on September 20, 2012
  18. science

    When astronauts travel into space, they can still see Earth and the moon. why is this possible? A. The sun shines in the windows of their space vehicle. B. They view earth and moon through a telescope. C. The sun's light reflects off earth and the moon. D.

    asked by Anonymous on March 27, 2010
  19. physics

    The Bohr model of the hydrogen atom consists of an electron travelling in a circular orbit of radius 5.29 x 10-11 m around a proton. The attraction between the two gives the electron the centripetal force required to stay in orbit. Calculate the: a.

    asked by matin on May 15, 2012
  20. Physics

    The average distance between Earth and the sun is 1.50e8 km. Calculate the average speed, in km/h, of Earth assuming a circular path about the sun. Use the equations v = 2(pi)r/T. You know that, for the Earth, T = 365.25 days. Convert that to hours (by

    asked by Jayd on August 17, 2007
  21. physics

    A spaceship travels with a speed of 0.3c as it passes by the Earth on its way to a distant star, as shown in the diagram below. The pilot of the spaceship measures the length of the moving ship as 40 m. 0.3 c Earth Determine its length as measured by a

    asked by Anonymous on May 29, 2013
  22. physics

    If the average speed of an orbiting space shuttle is 19600 mi/h, determine the time required for it to circle the Earth. Make sure you consider the fact that the shuttle is orbiting about 200 mi above the Earth's surface, and assume that the Earth's radius

    asked by savy on September 8, 2011
  23. Physics

    I have to make up my own standardized questions for a project, and I wanted to make sure I did my math right. Can someone please check it? Thanks!! If your mass was 60 kg, the earth’s mass was 6×10^24 kg, the radius of the earth was 6.4×10^6 meters,

    asked by Emily on April 14, 2008
  24. heeeeeeeeeeeelp physics

    Estimate the time difference between the longest day and the shortest day of a year in seconds if you lived on the Earth's equator with the assumptions below. Note: this is not the difference between solstices as we are adjusting the earth's rotation axis

    asked by clavin on June 5, 2013
  25. Science Help

    A satellite image shows a portion of the Namib Desert in Africa. This is an ancient, sandy desert with dunes that can be up to 305 m tall. The Namib Desert extends inland from the Atlantic Ocean between 80 km and 200 km and receives only 5 mm to 76 mm of

    asked by ¯\_('-')_/¯ on December 20, 2017
  26. Physics

    You are explaining why astronauts feel weightless while orbiting in the space shuttle. Your friends respond that they thought gravity was just a lot weaker up there. Convince them and yourself that it isn't so by calculating the acceleration of gravity 248

    asked by Dan on July 8, 2012
  27. Astronomy (algebra-based physics)

    Extrasolar planets There are currently 340 known extrasolar planets, i.e., planets around other suns. Most of them we infer only by their gravitational pull on their host stars, and a handful appear to dim the light of their host star as they transit in

    asked by Mark on March 4, 2009
  28. astronomy

    Assume that the mass of a sun-like star is 2.50 x 10^5 Earth masses and that its radius is about 101.0 times that of Earth. The density of Earth is about 5,500 kg/m^3. What is the density of this star?

    asked by carolyn on February 5, 2013
  29. Math (unit rates)

    Every 24 hours, Earth makes a full rotation around its axis. Earth's speed of rotation at the equator is 1,670 km per hour. What is the circumference of Earth's equator?

    asked by princessleaya on November 25, 2017
  30. Force of Gravity

    How far from Earth's surface would you have to travel to be 1/4 your weight. Give your answer in Earth radii. I know you have to travel twice the distance or 1 Earth radii... I just don't know how to mathematically show it. Please help.

    asked by Alison on September 11, 2014
  31. 6th math

    Every 24 hours, Earth makes a full rotation around its axis. Earth's speed of rotation at the equator is 1,670 km per hour. What is the circumference of Earth's equator?

    asked by princessleaya on November 15, 2017
  32. Physics

    Saturn has a radius of about 9.0 earth radii, and a mass 95 times the Earth’s mass. Estimate the gravitational field on the surface of Saturn compared to that on the Earth

    asked by Calitryphosa on December 16, 2011
  33. physics

    2. Saturn has a radius of about 9.0 earth radii, and a mass 95 times the Earth’s mass. Estimate the gravitational field on the surface of Saturn compared to that on the Earth

    asked by crystal on January 11, 2012
  34. English

    Can you please check these sentences for me? Thank you very much. 1)As to the content, English Romanticism focused above all on the “individual” as the subject of all meaningful experience and the centre of life and art. 2) The Romantics saw the

    asked by Franco on September 29, 2010
  35. astronomy

    Using the densities below, find what percentage of the Earth's mass is contained in its core. If Earth's core were adjusted in radius so that the core contained forty percent of the mass, by what factor would the radius of the Earth change compared with

    asked by roach on November 22, 2011
  36. Math

    The weight W of an object varies inversely as the square of the distance d from the center of the earth. At sea level (3978 mi from the center of the earth), an astronaut weights is 110lb. Find her weight when she is 459 mi above the surface of the earth

    asked by Miranda on May 13, 2009
  37. science

    a man has a mass of 80,0 kg is standing on the surface of the earth. a )calculate the magnitude of the attractive force (gravity) that the earth exerts on the man.(784n) b)how does your answer in a) compare to the magnitude of the force that the man exerts

    asked by mamare on February 28, 2016
  38. physic

    I don't understand this question at all. If you want to see the figure, let me know The figure below is a scaled representation of a planet's orbit with a semimajor axis of 1.528 AU. (Use the exact values you enter in previous answer(s) to make later

    asked by joy on February 17, 2018
  39. Math--Area

    Find the area of each regular polygon to the nearest tenth. Octagon with side length of 10 kilometers. Heres what I tried; but I don't know if im on the right track. Area=1/2 * Perimeter* Apothem Perimeter=base of octagon* number of sides Perimeter=10*8=80

    asked by natalie on April 4, 2007
  40. physics

    Which of the following correctly describe the gravitational attraction between Earth and the Moon? -The Earth and the Moon exert equal size gravitational forces on each other. -The gravitational force of the Moon on the Earth is towards the Moon. -Both the

    asked by Emily on October 4, 2012
  41. Calculus

    Explain fully please and thank you! =) Determine the point of intersection of the lines L1: r= (1,3,7) + s(1,2,-2),seR and L2: v=(0,2,-3) +t(1,1,4), teR. a) P(1,3,1) b P(1,3,7) c) The lines coincide d) no point of intersection

    asked by Melissa on April 7, 2012
  42. English

    Can you please check if it is everything right? Thank you. 1.I live in a small country village. My brother is a primary school student. 2.My parents are employees. 3.I’m a student at (of?) a technical high school with an emphasis on science. 4.I like

    asked by Franco on October 21, 2010
  43. Physics help - Earths force

    Is the force of the earth’s gravity on the sun stronger, weaker, or the same as the force of the sun’s gravity on the earth? Explain why the sun’s attraction affects the motion of the earth more than the earth’s attraction affects the sun’s

    asked by Emily on January 9, 2015
  44. physics

    The Moon's mass is 7.34 x 10^22 kg, and it is 3.8 x 10^8 away from Earth. Earth's mass if 5.97 x 10^24 kg. a. Calculate the gravitional force of attraction between Earth and the Moon. b. Find Earth's gravitional field at the moon. GIVEN: Moon's mass = 7.34

    asked by Heart on December 24, 2009
  45. physics plz help

    I need help in calculating work. following quantites are given. * G: 6.67E-11 *Mass of earth:5.98E24 *mass of satelightt:80kg *x(initial) center of the earth-7E6 m *x(final) center of the earth 12E6 m How do I make integral equation I need use 20 interval

    asked by jenny on April 7, 2014
  46. physics

    A planet has two satellite moons. Moon X has an orbital period of 2.13 days. Moon Y has an orbital period of about 3.53 days. Both moons have nearly circular orbits. Use Kepler's third law to find the distance of each satellite from the planet's center.

    asked by Angelina on February 17, 2012
  47. Physics I am lost please help

    A planet has two satellite moons. Moon X has an orbital period of 2.13 days. Moon Y has an orbital period of about 3.53 days. Both moons have nearly circular orbits. Use Kepler's third law to find the distance of each satellite from the planet's center.

    asked by Angelina on February 18, 2012
  48. Physics

    A planet has two satellite moons. Moon X has an orbital period of 2.13 days. Moon Y has an orbital period of about 3.53 days. Both moons have nearly circular orbits. Use Kepler's third law to find the distance of each satellite from the planet's center.

    asked by Angelina on February 18, 2012
  49. Physicsss

    A planet has two satellite moons. Moon X has an orbital period of 2.13 days. Moon Y has an orbital period of about 3.53 days. Both moons have nearly circular orbits. Use Kepler's third law to find the distance of each satellite from the planet's center.

    asked by Angelina on February 17, 2012
  50. history

    6. Do you find it curious that Budinot, an educated and highly assimilated Cherokee, would argue for removal in the name of preserving the Cherokee people? What does he fear if the Cherokee remain? What does this say about his attitude towards his own

    asked by rei on April 20, 2010
  51. Physics & Gravity

    The acceleration due to gravity on the moon is about one-sixth its value on earth. If a baseball reaches a height of 51 m when thrown upward by someone on the earth, what height would it reach when thrown in the same way on the surface of the moon? Answer

    asked by Jimmy on September 10, 2011
  52. 7th Grade Science About Earth Quakes

    Hi, I need some information about Earth Quakes. My question is: Where & Why do Earth Quakes occur? I'm not cheating or anything I just need some help with this topic for the project I'm doing about Earth Quakes right now. Please Help ME! Thanks :D

    asked by MusicLover14 on November 3, 2015
  53. Physics

    Given that the Earth's radius is 6.37x10^6 m and taking the earth's gravitational field at its surface to be 9.81N/kg, find the gravitational potential at the Earth's surface.

    asked by Claire on March 18, 2008
  54. Paul

    Determien the mass of the Sun using the known value for the period of the Earth and its distance from the Sun. I do not remeber how to do this F = ma = Fg = GmM/r^2 Period of earth 3.16 E 7 s radius earth to moon = 1.5 E 11 m

    asked by Physics on December 22, 2009
  55. physics

    a spaceship is traveling to the moon. at what point is is beyond the pull of the earth's gravity? a. above the atmosphere b. half way there c. when it's closer to the moon than the earth d. never beyond the pull of the earth

    asked by rory on December 8, 2008
  56. Science

    The weight of a body on the surface of the earth is 392N .What will be the weight of this body on a planet whose mass is double that of the earth and radius is four times that of the earth

    asked by Saranah on September 14, 2016
  57. English

    Can you pleae tell me which alternatives are possible? Thank you very much. 1, They believed a person (better: the individual) should be free from external rules. 2.The Romanics exalted the individual as the centre of life and art.This led to the view of

    asked by Franco on November 27, 2010
  58. English

    I find it difficult to look for appropriate synonyms. Here is what I found. I don’t know the meaning of “state residential treatment centre” . 1)A 13-year-old teenager throws a rock off a bridge over the motorway. The rock hits an oncoming car,

    asked by Henry2 on September 7, 2011
  59. english part 1

    Which of the following best expresses the writer's main idea in “Single Room, Earth View”? A. Space exploration leads to human progress. B. Space travel offers a unique view of Earth. C. Astronauts are highly trained scientists. D. Pollution is

    asked by Wahab on February 14, 2014
  60. Geography

    1.Which of the following describes members of an extended family? A. mother, father, sisters, and brothers B. aunts, uncles, cousins, grandparents C. neighbors and classmates D. parents and grandparents 2.Which of the following types of maps shows correct

    asked by Connexus on August 10, 2018
  61. physics

    A spaceship of mass m travels from the Earth to the Moon along a line that passes through the center of the Earth and the center of the Moon. (a) At what distance from the center of the Earth is the force due to the Earth three times the magnitude of the

    asked by Bob on December 2, 2011
  62. physics

    In a hydrogen atom, if the radius of the orbit of the electron is doubled, then its energy will ... a)Decrease by a factor of 2 b)Remain the same c)Increase by a factor of 2 d)Actually, it is not possible for the radius of the orbit to double e)Increase or

    asked by jude on April 4, 2010
  63. physics

    An observer on Earth sees an alien vessel approach at a speed of 0.44c. The Enterprise comes to the rescue, overtaking the aliens while moving directly toward Earth at a speed of 0.89c relative to Earth. What is the speed of one vessel as seen by the

    asked by Francis on June 11, 2017
  64. Math

    The diameter of Earth is about 8,000 mi. Suppose a jet is traveling around Earth at an altitude of 30,000 ft. How many miles will the jet travel in a complete circle aroung Earth? a. 94,247.8 mi. b. 25,156.7 mi. c. 38,000 mi. d. 8,005.7 mi.

    asked by Dylan on January 12, 2009
  65. physics

    Halley's comet moves about the sun in an elliptical orbit with its closest approach to the SUn being .59AU and its greatest distance being 35AU (1AU=Earth-sun distance) if the comet's speed at closest approach is 54km/s what is its speed when it is

    asked by cyndi on January 29, 2007
  66. physics

    This figure shows the force on a 0.1-kilogram mass at various distances from Earth. Notice that the force decreases as the square of the distance. Now, consider satellites A and B, both circling Earth. If A has ten times the mass of B but B is 1/10 of the

    asked by Sue on October 10, 2016
  67. Physics

    I still cannot solve this problem: Consider a spaceship located on the Earth-Moon center line (i.e. a line that intersects the centers of both bodies) such that, at that point, the tugs on the spaceship from each celestial body exactly cancel, leaving the

    asked by Lindsay on December 18, 2007
  68. physics

    need help with the following question. if earth has a mass of 6.0*10^24 kg and a radius 6.4*10^6 m: a) find the change in gravitational potential energy of a meteorite of mass 150 kg as it moves from an infinite distance to the earth's surface. b) with

    asked by rachel on September 24, 2011
  69. Earth Science

    My child is doing a project on the earth. He is trying to do a power point presentation on the earth. He ran across information that stated, "The earth is divided into several layers which have distinct chemicals and seismic properties". He would like to

    asked by Roderick on September 23, 2008
  70. ap physics

    (a) Calculate the angular momentum of Earth that arises from its spinning motion on its axis, treating Earth as a uniform solid sphere. J · s (b) Calculate the angular momentum of Earth that arises from its orbital motion about the Sun, treating Earth as

    asked by yesica on March 9, 2015
  71. Physics

    a) A distant spaceship carrying a red headlight, emitting light with wavelength 600 nm, is heading towards the earth. Observers on the earth detect the light from the headlight as ultraviolet light with wavelength 200 nm. What is the velocity of the

    asked by Bob on March 13, 2011
  72. College Physics

    n the approximation that the Earth is a sphere of uniform density, it can be shown that the gravitational force it exerts on a mass m inside the Earth at a distance r from the center is mg(r/R), where R is the radius of the Earth. (Note that at the the

    asked by Amelie on March 9, 2011
  73. Physics

    In the approximation that the Earth is a sphere of uniform density, it can be shown that the gravitational force it exerts on a mass m inside the Earth at a distance r from the center is mg(r/R), where R is the radius of the Earth. (Note that at the the

    asked by Amelie on March 9, 2011
  74. humanities

    Summarize each event and explain how the changing attitudes of the time were expressed through these various political events and movements such as civil rights, gender equality, and warDescribe how the arts (music, literature, and visual art) were

    asked by Anonymous on July 20, 2011
  75. Science. Answer Check

    1. A student studying a circuit diagram of a lightbulb, battery, and a switch correctly identifies it as a closer circuit. In this diagram, The lightbulb would be a. an insulator b. on*** c. disconnected d. off 2. The focus of gravity on an object on the

    asked by Jay on December 6, 2016
  76. Science 7

    1. A student studying a circuit diagram of a lightbulb, battery, and a switch correctly identifies it as a closer circuit. In this diagram, The lightbulb would be a. an insulator b. on*** c. disconnected d. off 2. The focus of gravity on an object on the

    asked by cat on November 1, 2016
  77. science

    lunar probes: what else does a lunar probe have other than a camera? i need to know today becasue it is for aproject and it is due tomorrow please help!!!!!! You will find a description of some of the first lunar probes that actually landed on the moon at

    asked by gabby on March 18, 2007
  78. Math

    The radius of Earth is 3,959 miles. A spacecraft orbits 6 miles above the surface of Earth. The spacecraft completes 220° of a revolution around Earth in one day. What is the average speed of the spacecraft?

    asked by Chris on November 8, 2012
  79. PHYSICS

    THE MASS OF VENUS IS 81.5% OF THE EARTH AND ITS RADIUS IS 94.9% THAT OF THE EARTH. A)COMPUTE THE ACCELERATION DUE TO GRAVITY ON THE SURFACE OF VENUS FROM THESE DATA.B)IF A ROCK WEIGHS 75.0N ON EARTH,WHAT WOULD IT WEIGH ON THE SURFACE OF VENUS?

    asked by GIFT on August 4, 2014
  80. Physics

    You are flying to the Moon. Find the point at which the gravitational attractions of Earth and Moon on you will be equal and opposite. Given: radius of the moon: 1.74*10^6 m radius of the earth: 6.38*10^6 m orbital radius of the moon: 3.8*10^8 m Not enough

    asked by Katie on June 14, 2007
  81. physics problem ???

    A projectile is ejected from a 25-m high tower with a velocity of 40 m/s at an angle of 30 degrees to the horizontal first on Earth and then on Mars. What is the ratio of the time taken to hit the ground on Mars compared to Earth?? (Assume gravity of mars=

    asked by mK on December 2, 2010
  82. Math

    There are about 7 billion people on Earth. Suppose that they all lined up and held hands, each person taking about 2 yards of space. a. How long a line would the people form? b. The circumference of the Earth is about 25,000 miles at the equator. How many

    asked by Brandon on November 17, 2013
  83. jay kay public

    Consider a planet in space whose mass is twice that of earth and radius is thrice that of earth what will be the weight of a body on this planet if its weight on the earth is 900N ??

    asked by adi on December 8, 2015
  84. Social Studies

    What does “geography” mean in literal sense? a. the study of the human elements of Earth b. to describe Earth*** c. the study of the physical elements of Earth d. none of the above

    asked by Kaai97 on February 4, 2016
  85. Science

    How often does high tide occur on Earth? A. It is a high tide somewhere on Earth constantly*** B. It is a high tide somewhere on Earth only at midnight C. It is a high tide somewhere on Earth once a week D. It is a high tide somewhere on Earth once a month

    asked by HI mom on November 13, 2018
  86. Science

    How often does high tide occur on Earth? A. It is a high tide somewhere on Earth constantly B. It is a high tide somewhere on Earth only at midnight*** C. It is a high tide somewhere on Earth once a week D. It is a high tide somewhere on Earth once a month

    asked by Henry Hart on November 13, 2018
  87. 4th grade math

    it takes jupiter 12 years to orbit the sun. how many days does it take jupiter to orbit the sun?. add 3 days for leap years

    asked by mythreyee on December 20, 2013
  88. science

    Meteorites can make large depressions on Earth’s surface when they make impact. Why are so few of these depressions visible on Earth’s surface? • Earth is constantly changing it’s topography due to volcanic activity, or processes such as

    asked by Payton on April 23, 2018
  89. physics

    While watching ocean waves at the dock of the bay, Otis notices that 8 waves pass beneath him in 30 seconds. He also notices that the crests of successive waves exactly coincide with the posts that are 3 meters apart. What are the period, frequency,

    asked by haylee on February 28, 2011
  90. physics

    While watching ocean waves at the dock of the bay, Otis notices that 13 waves pass beneath him in 32 seconds. He also notices that the crests of successive waves exactly coincide with the posts that are 7 meters apart. What are the period, frequency,

    asked by anna on April 15, 2011
  91. Physics

    While watching ocean waves at the dock of the bay, Otis notices that 13 waves pass beneath him in 26 seconds. He also notices that the crests of successive waves exactly coincide with the posts that are 5 meters apart. What are the period, frequency,

    asked by Kevin on March 1, 2011
  92. Physics

    During the war in iraq, the us military was extremely successful at detecting and striking enemy targets. many news correspondants suggested the coalition forces had a spy satellite at an altitude of only a few hundred kilometers permanently positioned 34

    asked by Capreeca on July 17, 2011
  93. Physics

    Some spacecraft design uses a solar sail made of aluminized plastic. As sunlight reflects off the sail, radiation pressure drives the spacecraft outward away from the sun. a. If the sail material has a density of 700.0 kg/m3, what is the maximum thickness

    asked by Daniel on March 11, 2011
  94. physics please help!!

    A satellite dish is designed to pick up radio waves from geostationary satellites about 36000 km about the Earth's surface. If the dish's surface is a part of a sphere of radius R, where should the receiver be placed compared to the center of the dish? 1.

    asked by archi on November 24, 2011
  95. Physics

    Sally has a mass of 50.0kg and earth has a mass of 5.98X10^24kg. The radius of earth is 6.371x10^6m. A)What is the force of gravitational attraction between sally and earth? B)What is Sally's weight?

    asked by Sam on February 23, 2016
  96. science

    a crew of astronauts leaves earth on a Monday , lands on the moon on a Thursday. they and on the side of the moon facing away from the earth. on what day would the astronauts be able to see earth from the moon, explain

    asked by robin a on October 14, 2015
  97. Physics

    Take into account the Earth's rotational speed (1 rev/day) and determine the necessary speed, with respect to the Earth, for a rocket to escape if fired from the Earth at the equator in a direction a) eastward; b) westward; c) vertically upward. The

    asked by Steve on March 19, 2008
  98. Physics

    Take into account the Earth's rotational speed (1 rev/day) and determine the necessary speed, with respect to the Earth, for a rocket to escape if fired from the Earth at the equator in a direction a) eastward; b) westward; c) vertically upward. The

    asked by Steve on March 19, 2008
  99. Physics Classical Mechanics

    The mean distance from the center of the earth to the center of the moon is rem = 3.84 × 108 m. The mass of the earth is me = 5.98 × 1024 kg and the mass of the moon is mm = 7.34 × 1022 kg. The mean radius of the earth is re = 6.37 × 106 m. The mean

    asked by Anonymous on October 28, 2013
  100. puzzles

    does this puzzle mean "down to earth" ------------- this is a box [ ] [ ] [ ] [ earth earth ] -------------

    asked by Delaney on April 13, 2009