Question

The orbital speed of an artificial satellite very close to the surface of the earth is$V _ { o }$. Then the orbital speed of another artificial satellite at a height equal to three times the radius of the earth is

• A. $4 V _ { o }$
• B. $2 V _ { o }$
• C. $0.5 V _ { o }$
• D. $4 V _ { o }$

Answer 1

Answer: (C)

$0.5 V _ { o }$

Answer 2

$v \propto \frac { 1 } { \sqrt { r } }$ If $r = R$ then $v = V _ { 0 }$

If $r = R + h = R + 3 R = 4 R$then $v = \frac { V _ { 0 } } { 2 } = 0.5 V _ { 0 }$