physics
posted by Amber .
On July 15, 2004, NASA launched the Aura spacecraft to study the earth's climate and atmosphere. This satellite was injected into an orbit 705 {\rm km} above the earth's surface, and we shall assume a circular orbit.
How many hours does it take this satellite to make one orbit? (T=?hours)
How fast (in {\rm km/s} )is the Aura spacecraft moving? (v=?km/s)

A boat propelled so as to travel with a speed of 0.50m/s in still water, moves directly ( in a straight line) across the river that is 60m wide. The rivers flows with a speed of 0.30m/s. How long in a seconds does it take the boat to across the river?

On the earth surface g = GM/R^2
And at the height h
g" = GM/ [R+h]^2
g" = R^2/ [ R+h]^2•g
g" = {R/ [ R+h] }^2•g
g" = {6378/ 7083}^2•9.81 = 7.95 m/s^2
T^2 = 4π^2•(R+h) /g"
T^2 = 4π^2•7083 /7.95
T = 187.54s = 0.052 hour.
v = 2•π •[R+h] / T
v = 2•π •[7.083] / 187.54s
v = 0.24 km /s 
I've mistaken in the previous post.
New version:
m•a(norm) = GM/ [R+h] ^2,
m•v^2/(R+h) = GM/ [R+h] ^2,,
v = sqrt[GM/(R+h)] =sqrt [6.67•10^11•5.97•10^24/7.1•10^6] =
= 7490 m/s =7.49 km/s
T = 2 •π(•R+h)/v =2 •π•7.1•10^6/7490= =5960 s =1.65 h
Respond to this Question
Similar Questions

Physics
A satellite of mass 220 kg is launched from a site on Earth's equator into an orbit at 200 km above the surface of Earth. (a) Assuming a circular orbit, what is the orbital period of this satellite? 
Physics
A satellite of mass 210 kg is launched from a site on Earth's equator into an orbit at 210 km above the surface of Earth. (a) Assuming a circular orbit, what is the orbital period of this satellite? 
physics
Two Earth satellites, A and B, each of mass m, are to be launched into circular orbits about Earth's center. Satellite A is to orbit at an altitude of 7460 km. Satellite B is to orbit at an altitude of 20500 km. The radius of Earth … 
physics
Two Earth satellites, A and B, each of mass m, are to be launched into circular orbits about Earth's center. Satellite A is to orbit at an altitude of 7460 km. Satellite B is to orbit at an altitude of 20500 km. The radius of Earth … 
Physics
A communications satellite with a mass of 450 kg is in a circular orbit about the Earth. The radius of the orbit is 2.9×10^4 km as measured from the center of the Earth. Calculate the weight of the satellite on the surface of the … 
Physics help PLZ!!
Estimate the energy required from fuel to launch a 1465 kg satellite into orbit 1375 km above the Earth’s surface. Consider two cases: (a) the satellite is launched into an equatorial orbit from a point on the Earth’s equator, … 
physics
Estimate the energy required from fuel to launch a 1465 kg satellite into orbit 1375 km above the Earth’s surface. Consider two cases: (a) the satellite is launched into an equatorial orbit from a point on the Earth’s equator, … 
physics
A satellite of mass 225 kg is launched from a site on Earth's equator into an orbit at 200 km above the surface of Earth. (The mass of the Earth is 5.98 1024 kg, and the radius of the Earth is 6.38 103 km.) (a) Assuming a circular … 
physics
A satellite of mass 205 kg is launched from a site on Earth's equator into an orbit at 200 km above the surface of Earth. (a) Assuming a circular orbit, what is the orbital period of this satellite? 
physics
NASA launches a satellite into orbit at a height above the surface of the Earth equal to the Earth's mean radius. The mass of the satellite is 550 kg. (Assume the Earth's mass is 5.97 1024 kg and its radius is 6.38 106 m.) (a) How …