Newest questions and responses by keitanako
  1. astronomy

    If the planet is in an edge-on orbit, what would its mass be (in kg)?

    asked on June 25, 2014
  2. astronomy

    Hydrogen accounts for 71% of the Sun's mass today. If only one tenth of that Hydrogen burns into Helium, how long could the Sun keep shining at its present luminosity? Note that Hydrogen fusion has an efficiency of about 0.7% Time in years:

    asked on May 14, 2014
  3. Astronomy

    Put the following in order from earliest to latest. In doing so, assume that the Nice model occurred as described and that the Grand Tack model also occurred as described. 1) The formation of Jupiter 2) The inward migration of Jupiter due to gas forces 3)

    asked on May 13, 2014
  4. science

    How many DALYs are lost by a person who has a life expectancy of 74, contracts HIV/AIDS at the age of 40 and lives until the age of 60? This person receives antiretroviral medication two years after she/he contracts HIV/AIDS until she/he dies. [The

    asked on May 5, 2014
  5. astronomy

    Rank the following hypothetical planets -- all of which have the same total mass and same radius -- from lowest moment of inertia to highest moment of inertia: 1) A uniform sphere of mixed up rock and iron 2) A rocky planet with an iron core 3) A rocky

    asked on April 14, 2014
  6. astronomy

    Imagine that you live in a distant galaxy far far away. This galaxy is in a different universe, and so may have different cosmology. It seems that in this distant universe, all galaxies have the same luminosity, which you have worked out is 7.0*10^30 W.

    asked on April 11, 2014
  7. astronomy

    Before Dark Energy could be discovered, several preconditions needed to be in place. Tick all the factors below which were necessary for the discovery of dark energy. 1. Large format detectors for wide field imaging 2. Radio interferometers 3. Large

    asked on April 11, 2014
  8. Astronomy

    Another star cluster ("star cluster 2") lies 7.4 Mega-parsecs from the starship, and has an apparent radius of 6.3 arc seconds. You would like to know how big it is. Is it the same size as galaxies in our universe (i.e. tens of kilo-parsecs) or only as big

    asked on April 2, 2014
  9. statistics

    The highest point in the scatter is the point for Illinois, at 1807. The two just below it, at 1778 and 1777, are for Minnesota and Iowa. The lowest points are at 1391 and 1385, for Maine and D.C. respectively. Pick all the options that are correct. The

    asked on March 22, 2014
  10. Chemistry

    Last week we drew Lewis dot structures of azide (N31-), a crucial component in automobile collision safety airbags. During an impact, a sensor ignites a detonator cap that sets off the following rapid reaction: 2NaN3(s) → 2Na(s) + 3N2(g) Part A What

    asked on March 19, 2014
  11. Chemistry

    A 10.00 gram solid sample consisting of a mixture of sodium chloride and potassium sulfate is dissolved in 100.0 mL of water is combined with another 200.0 mL solution that contains excess aqueous lead(II) nitrate. Upon mixing the two solutions, a solid

    asked on March 18, 2014
  12. Chemistry

    2NaN3(s) -> 2Na(s) + 3N2(g) What mass of sodium azide should be loaded in the device to ensure full inflation of the same air bag if the actual reaction can be expected to proceed to give only 83% yield of nitrogen gas?

    asked on March 18, 2014
  13. chemistry

    2C3H6(g) + 2NH3(g) + 3O2(g) -> 2C3H3N(g) + 6H2O(g) A 150.0 liter steel reactor at 25 ºC is filled with the following partial pressures of reactants: 0.500 MPa C3H6, 0.800 MPa ammonia, and 1.500 MPa oxygen gas. If the reaction proceeds to 90% yield, and no

    asked on March 18, 2014
  14. Chemistry

    A 108 mL gas sample has a mass of 77.96 mg at a pressure of 1140 mmHg and a temperature of 183 °C. Assume ideal gas behavior and a completely insulated system, and please don’t forget units with your answers. The system is cooled. Calculate the

    asked on March 10, 2014
  15. Astronomy

    Consider dropping a Professor with an estimated mass of 80 kg from a safe, large distance, onto a SMBH with a mass of 10^7M⊙. The Prof makes an impact at the Schwarzschild radius, whereby he converts all of the gained kinetic energy into radiation

    asked on March 9, 2014
  16. Astronomy

    1. Consider an asteroid of radius 2 km and density 2,500 kg/m^3 impacting the Earth. When it collides with the surface its kinetic energy is, to a large extent, dumped into the environment, some as heat vaporizing rock and some as mechanical energy

    asked on December 9, 2013
  17. Astronomy

    The volume of a ball is given in terms of its radius by V=(4*pi/3)*R^3. Use this to find the average density of Nursat, i.e. the mass per unit volume. Use Earth'€™s mass in kg from the Table of Constants to express your answer in kg/m3.

    asked on December 9, 2013
  18. Astronomy

    1. At opposition, Nursat(is observed to be in opposition every 374 days.) is observed to subtend an angular radius of 7.1523 arcseconds. Use this and the conversion factors in our Table of Constants to find the radius of Nursat in km. 2. Nursat has a moon,

    asked on December 9, 2013
  19. Astronomy

    1. In this collection of problems we will try to use what we have learned to see what information about a hypothetical Solar System planet we can extract from observations. The planet, Nursat, is observed to be in opposition every 374 days. Use this

    asked on December 9, 2013
  20. Astronomy

    For an object of mass m in a circular orbit of radius R under the gravitational influence of a center of mass M, find an expression for the total energy, the sum of kinetic and potential energy (with potential energy at infinite distance set to zero), in

    asked on December 9, 2013
  21. Astronomy

    A possible trajectory for sending a spacecraft to Mars is an elliptical orbit with Earth at its perihelion and Mars at its aphelion. The craft would be launched out of low-Earth orbit by a quick burst of rockets into solar orbit, and would then "coast''

    asked on December 9, 2013
  22. Astronomy

    In fact, more precise calculations suggest that ISON was on a hyperbolic, unbound orbit. How much more precise? Find the minimal speed with which the comet would have had to be moving when observed at perihelion in order to eventually escape the Solar

    asked on December 9, 2013
  23. Astronomy

    1. Sun-grazing comet ISON disintegrated on November, 2013. Observation of the comet suggested an elliptical orbit with period 581,480 years. What would this predict for the distance from the Sun at the orbit’s aphelion, the farthest point from the

    asked on December 9, 2013
  24. Physics(Help!!!!!!)

    A stick of length l = 65.0 cm rests against a wall. The coefficient of static friction between stick and the wall and between the stick and the floor are equal. The stick will slip off the wall if placed at an angle greater than θ = 39.0 degrees. What

    asked on December 9, 2013
  25. Physics(Help!!!!)

    A person of mass m2= 85.0 kg is standing on a rung, one third of the way up a ladder of length d= 3.0 m. The mass of the ladder is m1= 15.0 kg, uniformly distributed. The ladder is initially inclined at an angle θ= 35.0∘ with respect to the

    asked on December 9, 2013
  26. Physics(URGENT!!!!)

    A ruler stands vertically against a wall. It is given a tiny impulse at θ=0∘ such that it starts falling down under the influence of gravity. You can consider that the initial angular velocity is very small so that ω(θ=0∘)=0. The ruler

    asked on December 9, 2013
  27. Astronomy

    1. Imagine that the Earth¡¦s spin were to be reversed, so that the planet rotated about its axis from East to West, at the same rate at which it now rotates from West to East. If Earth¡¦s orbital motion about the Sun were unchanged, which of these

    asked on December 5, 2013
  28. Astronomy

    Star Right Ascension Declination Aldebaran 4h 36m 16¢X 31' Miaplacidus 9h 13m -69¢X 42' Deneb 20h 41m 45¢X 20' Regulus 10h 08m 12¢X 18' Hadar 14h 04m -60¢X 24' 1.If Aldebaran is crossing your local meridian, how long would you need to wait to see

    asked on December 5, 2013
  29. Physics(IMPORTANT)

    An object of mass m=80 kg moves in one dimension subject to the potential energy U(x)=(λ/4)(x^2-a^2)^2+(b/2)x^2 Here we use λ=3kg/(m^2s^2), a=7m, and b=77kg/s^2. (b) Find a stable equilibrium point x0 such that x0 is positive. (in meters) x0= (c) Do

    asked on November 1, 2013
  30. Physics(IMPORTANT)

    A block of mass m = 2 kg on a horizontal surface is connected to a spring connected to a wall (see figure). The spring has a spring constant k =10 N/m. The static friction coefficient between the block and the surface is mμs =0.7 , and the kinetic

    asked on November 1, 2013
  31. Physics(IMPORTANT)

    An airliner makes an emergency landing with its nose wheel locked in a position perpendicular to its normal rolling position. The forces acting to stop the airliner arise from friction due to the wheels and from the breaking effort of the engines in

    asked on November 1, 2013
  32. Physics(IMPORTANT)

    A small ball of mass m=0.60 kg hangs from a massless string of length l=0.9 m. The ball travels in a vertical circle and its speed at the bottom is v0=6.0 m/s (see figure). Neglect all friction and air drag, and use g=10m/s^2 for the gravitational

    asked on November 1, 2013
  33. Physics(IMPORTANT)

    A small object of mass m= 90 kg slides down a spherical dome of radius R=12 m without any friction. It starts off at the top (polar angle θ=0) at zero speed. Use g=10 m/s2. (See figure) (a) What is the magnitude of the force (in Newtons) exerted by the

    asked on November 1, 2013
  34. Physics(IMPORTANT)

    Two skaters of mass m1=50kg and m2=70kg are standing motionless on a horizontal ice surface. They are initially a distance L=7.0 meters apart. They hold a massless rope between them. After pulling the rope, the skater of mass m1 has moved a distance l=2.0

    asked on November 1, 2013
  35. Physics(IMPORTANT)

    A meteorite of mass 1*10^4kg is approaching head-on a planet of mass 5*10^29kg and radius 5*10^4km. Assume that the meteorite is initially at a very large distance from the planet where it has a speed 3*10^2km/s. Take 6.67*10^-11. Determine the speed of

    asked on November 1, 2013
  1. astronomy


    posted on April 11, 2014
  2. statistics

    the answer is wrong...

    posted on March 23, 2014
  3. Chemistry

    Thank you, I know how to do it.

    posted on March 19, 2014
  4. Chemistry

    Hi, Bob. But how to get (MMPbCl2/2*MMNaCl) and (MMPbSO4/MMK2SO4). Because it is confusing to me. Can you show the step more clearly. Thank you? I just can do step 1, which is X=10-Y. But step 2, it is bit confused. I can't get the meaning.

    posted on March 19, 2014
  5. Chemistry

    Sorry, I have forgotten to give the information. This question has part a, which is "What mass of sodium azide must be completely reacted to inflate an air bag to 65.0 liters at 20.0 ºC and 1.06 atm?" Please help me because I have calculated many time,

    posted on March 19, 2014
  6. Classical Mechanics Physics - Urgent help please

    After finding f_x, use that value in the equation Torque=I_cm *alpha equation (containing F_y and F_x), i think you don't need to find a_y. May I ask how to apply to the equation, please?

    posted on December 9, 2013