Q. A research satellite of mass $200\ kg$ circles the earth in an orbit of average radius $3R/2$ where $R$ 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) $880\ N$
B) $889\ N$
C) $890\ N$
D) $892\ N$
Explanation
(b) $g^{'} = g\left( \frac{R}{R + h} \right)^{2} = g\left( \frac{R}{3R/2)} \right)^{2} = \frac{4}{9}g\ \ \lbrack g = 10m/s{ec}^{2}\rbrack$
$\therefore W^{'} = \frac{4}{9} \times mg = \frac{4 \times 200 \times 10}{9} = 889\ N$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.