12th grade physic

Q. A satelite is in a circular orbit around the earth with a period of 6.0 hours. A retrorocket thruster is fired which slows the satelite down to half its speed and places it in a new orbit.

G = 6.67 x 10 power of -11 N.m2/kg2

mass of earth = 5.98 x10 power of 24 Kg

radius of the earth = 6,38 x 10 power of 6 m

a) Find the satellites new speed after the thruster is fired.
Answer = 2400m/s

b) Find the altitude of the satelites new orbit.
Answer = 61000000m

I know the answers for both questions a) and b) and solutions to a) but i don't know the solutions to b)

How did they get 61000000m for question b)???

asked by orange
  1. a) Use G Me/R^3 = 4 pi^2/P^2 for the original orbit radius, R.
    P = 6 h = 21,600 s
    R^3 = G Me P^2/(4 pi^2)
    = 4.73*10^21
    (This is Keper's third law)
    R = 1.678*10^7 m = 2.63 Re
    original orbit speed
    = 2 pi R/(21,600 s) = 4.88*10^3 m/s
    Final orbit speed = half of above = 2440 m/s. They must have rounded it to 2 significant figures to get 2400 m/s.

    b) If the new orbit is circular also, it will require some special maneuvers. A short retro burn will yield an elliptical orbit. If we assume a new circular orbit at half the speed, use the fact that V^2 * R = constant for circular orbits. If V is reduced by half, R must increase by a factor of 4.

    R = 4 * 1.68*10^7 = 6.72*10^7 m

    That does not quite agree with your "book answer" of 6.1*10^7. Check my numbers

    posted by drwls

Respond to this Question

First Name

Your Response

Similar Questions

  1. Physics

    An Earth satellite moves in a circular orbit at a speed of 5800 m/s. a)What is the radius of the satellite's orbit? b) What is the period of the satellites orbit in hours?
  2. Physics

    A 50-kg satellite circles the Earth in an orbit with a period of 120 min. What minimum energy is required to change the orbit to another circular orbit with a period of 180 min? (Earth: radius = 6.4  106 m, mass = 6.0
  3. Physics Classical Mechanics

    A planet has a single moon that is solely influenced by the gravitational interaction between the two bodies. We will assume that the moon is moving in a circular orbit around the planet and that the moon travels with a constant
  4. physics

    A satellite moves in a circular orbit around Earth at a speed of 4390 m/s (a) Determine the satellite's altitude above the surface of Earth.(meters) (b) Determine the period of the satellite's orbit. (hours) I used the equation
  5. physics180

    A satellite is in circular orbit at a height R above earth's surface. a)find orbital period. b)what height is required for a circular orbit with a period double that found in part (a)?
  6. physics

    A geosynchronous Earth satellite is one that has an orbital period equal to the rotational period of the Earth. Such orbits are useful for communication and weather observation because the satellite remains above the same point on
  7. Physics

    A 50 kg satellite circles the earth in an orbit with a period of 110 min. What minimum energy E is required to change the orbit to one with a period of 320 min? Assume both the initial and final orbits are circular. The Earth’s
  8. physics

    What is the radius of a communications satellite’s orbital path that is in a uniform circular orbit around Earth and has a period of exactly 24.0 hours (86,400 seconds). (Measurement is from the center of Earth.) G = 6.67 ×
  9. Physics

    A satellite in circular orbit around the earth has an orbital speed of 5 km/s. What is the period of the orbit? Assume the mass of the Earth is 5.98e24 kg.
  10. Phyisics

    A spy satellite is in circular orbit around Earth. It makes one revolution in 6.02 hours. How high above Earth's surface is the satellite Use keplers law, comparing the moon period and distance from Earth to the Satellite. There

More Similar Questions