A satellite orbits a planet of unknown mass in a circular orbit of radius 2.3 x 104 km. The gravitational force on the satellite from the planet is 6600 N. What is the kinetic energy of the satellite

Respuesta :

Answer:

The  kinetic energy is [tex]KE = 7.59 *10^{10} \ J[/tex]

Explanation:

From the question we are told that

       The  radius of the orbit is  [tex]r = 2.3 *10^{4} \ km = 2.3 *10^{7} \ m[/tex]

       The gravitational force is  [tex]F_g = 6600 \ N[/tex]

The kinetic energy of the satellite is mathematically represented as

       [tex]KE = \frac{1}{2} * mv^2[/tex]

where v is the speed of the satellite which is mathematically represented as

     [tex]v = \sqrt{\frac{G M}{r^2} }[/tex]

=>  [tex]v^2 = \frac{GM }{r}[/tex]

substituting this into the equation

      [tex]KE = \frac{ 1}{2} *\frac{GMm}{r}[/tex]

Now the gravitational force of the planet is mathematically represented as

      [tex]F_g = \frac{GMm}{r^2}[/tex]

Where M is the mass of the planet and  m is the mass of the satellite

 Now looking at the formula for KE we see that we can represent it as

     [tex]KE = \frac{ 1}{2} *[\frac{GMm}{r^2}] * r[/tex]

=>    [tex]KE = \frac{ 1}{2} *F_g * r[/tex]

substituting values

       [tex]KE = \frac{ 1}{2} *6600 * 2.3*10^{7}[/tex]

         [tex]KE = 7.59 *10^{10} \ J[/tex]