Compute and find an answer

The escape velocity, V is the speed required to get away from the gravitational influence of a planet and it is given by the formula V=SQRT(2GMplanet/R) where is the distance from the center of the planet, Mplanet is the mass of the planet, and G is a number called the Gravitational constant. The escape velocity from the surface of the earth, where Re is the Radius of the earth, is 25,000 Mi/hr. What would the escape velocity be in units of Mi/hr from a starting point at a height 3Re above the earth's surface. Note: SQRT stands for square root sign, for example 2=SQRT(4)

Compute and find an answer

A main sequence blue star, called the Blue Phoenix, has a mass of more than 50 Msun, and is in a circular orbit about the center of the Galaxy. Also the Blue Phoenix is a distance of 20,000 L-Y from the center of the Galaxy and it's orbital speed is estimated at 280Km/sec. How many years will it take for this bright star to complete one orbit around the galaxy? What stage of life will this star be in by the time it completes this one revolution?Discuss your rationale for reaching your conclusion. (Msun is the mass of the sun, and the Blue Phoenix is an imaginary star, you will not find it on any star chart)

calculating sidereal time

Calculate local sidereal time for noon on December 4 in Green Bank West Virginia USA.

I need a formula to solve a problem and don't know which one to use.

The gas shell of a planetary nebula is expanding (away from the central star) at 20 km/s. The nebula currently has a diameter of 1 light year. What is the age of the planetary nebula(time since the gas was ejected).

Saturn's rings

If Saturn's rings are not solid, why do they look solid when viewed through a telescope?