Asatellite is in a circular orbit about the earth (me = 5.98 x 10^24 kg). the period of the satellite is 1.26 x 10^4 s. what is the speed at which the satellite travels?

Explanation:

According to the Third Kepler’s Law of Planetary motion:

  (1)

Where;:

is the period of the satellite

is the Gravitational Constant and its value is

is the mass of the Earth

 is the semimajor axis of the orbit the satllite describes around the Earth (as we know it is a circular orbit, the semimajor axis is equal to the radius of the orbit).

On the other hand, the orbital velocity is given by:

  (2)

Now, from (1) we can find , in order to substitute this value in (2):

  (3)

  (4)

  (5)

Substituting (5) in (2):

  (6)

  (7)  This is the speed at which the satellite travels

the device is called “ rocket engine”

in simple terms, the principle states that the buoyancy force on an object is equal to the weight of the fluid displaced by the object, or the density of the fluid multiplied by the submerged volume times the gravitational acceleration, g. this is also known as upthrust.