Two satellites P and Q are moving in different circular orbits around the Earth (radius 𝑅). The heights of P and Q from the Earth surface are β„ŽP and β„ŽQ, respectively, where β„ŽP = 𝑅/3. The accelerations of P and Q due to Earth’s gravity are 𝑔P and 𝑔Q, respectively. If 𝑔P/𝑔Q = 36/25, what is the value of β„ŽQ? (A) 3𝑅/5 (B) 𝑅/6 (C) 6𝑅/5 (D) 5𝑅/6

 Given two satellites P and Q moving in circular orbits around the Earth, we need to find the height 

hQ of satellite Q from the Earth's surface. The height of satellite P is hP=R3, where R is the Earth's radius. The accelerations due to Earth's gravity for P and Q are gP and gQ respectively, with the ratio gPgQ=3625.

  1. Determine the orbital radius of satellite P:

    rP=R+hP=R+R3=4R3
  2. Relate the accelerations using Newton's law of gravitation:

    gPgQ=(rQrP)2

    Given gPgQ=3625, we have:

    (rQrP)2=3625    rQrP=65
  3. Calculate the orbital radius of satellite Q:

    rQ=65×rP=65×4R3=24R15=8R5
  4. Determine the height hQ:

    hQ=rQR=8R5R=8R55R5=3R5

Thus, the value of hQ is A.

Comments