Question:

A remote sensing satellite of Earth revolves in a circular orbit at a height of 0.25 × 10⁶ m above the surface of Earth. If Earth's radius is 6.38 × 10⁶ m and g = 9.8 ms⁻², then the orbital speed of the satellite is:

7.76kms⁻¹

6.67kms⁻¹

8.56kms⁻¹

9.13kms⁻¹

Orbital speed: V = √(GM/r) = √(GM/(R+h)) = √(gR²/(R+h)) = √(9.8 × (6.38 × 10⁶)²/(0.25 × 10⁶ + 6.38 × 10⁶)) = 7.76 km/s