# keitanako

Newest questions posted by keitanako-
## astronomy

If the planet is in an edge-on orbit, what would its mass be (in kg)? -
## 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: -
## 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) -
## 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 -
## 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 -
## 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. -
## 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 -
## 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 -
## 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 -
## 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) â†’ 2Na(s) + 3N2(g) Part A What -
## 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 -
## 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? -
## 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 -
## 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 donâ€™t forget units with your answers. The system is cooled. Calculate the -
## Astronomy

Consider dropping a Professor with an estimated mass of 80 kg from a safe, large distance, onto a SMBH with a mass of 10^7MâŠ™. The Prof makes an impact at the Schwarzschild radius, whereby he converts all of the gained kinetic energy into radiation -
## 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 -
## 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. -
## 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, -
## 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 -
## 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 -
## 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'' -
## 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 -
## 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 orbitâ€™s aphelion, the farthest point from the -
## 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 Î¸ = 39.0 degrees. What -
## 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 Î¸= 35.0âˆ˜ with respect to the -
## Physics(URGENT!!!!)

A ruler stands vertically against a wall. It is given a tiny impulse at Î¸=0âˆ˜ such that it starts falling down under the influence of gravity. You can consider that the initial angular velocity is very small so that Ï‰(Î¸=0âˆ˜)=0. The ruler -
## 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 -
## 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 -
## Physics(IMPORTANT)

An object of mass m=80 kg moves in one dimension subject to the potential energy U(x)=(Î»/4)(x^2-a^2)^2+(b/2)x^2 Here we use Î»=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 -
## 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 mÎ¼s =0.7 , and the kinetic -
## 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 -
## 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 -
## 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 Î¸=0) at zero speed. Use g=10 m/s2. (See figure) (a) What is the magnitude of the force (in Newtons) exerted by the -
## 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 -
## 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