Question

A research satellite of mass 200 kg circles the earth in an orbit radius $\frac { 3 \mathrm { R } _ { \mathrm { E } } } { 2 }$ where is the radius of the earth. Assuming the gravitational pull on a mass of 1 kg on the earth’s surface to be 10 N, the pull on the satellite will be

• A. 890 N
• B. 889 N
• C. 885 N
• D. 892 N

Answer 1

Answer: (B)

889 N

Answer 2

Force between earth and mass of 1 kg is

….. (i)

Where is the mass of the earth and $\mathrm { R } _ { \mathrm { E } }$ is the radius of the earth respectively.

Force between earth and satellite is

….. (ii)

Divide (ii) by (i), we get

$\frac { \mathrm { F } ^ { \prime } } { \mathrm { F } } = \frac { 800 } { 9 }$

$\mathrm { F } ^ { \prime } = \frac { 800 \mathrm {~F} } { 9 } = \frac { 800 } { 9 } \times 10 \mathrm {~N}$ ( F = 10 N (Given)