Question

The work done by the force of gravity on a satellite moving around the earth is

[M – mass of earth, m – mass of satellite, r – radius of orbit]

• A. $\frac{m{v}^2}{2\pi }$
• B. $2mv62\pi$
• C. $\frac{m{v}^2}{r}$
• D. Zero

Answer 1

The correct option is D Zero

Work done, $W=Fscos\theta$

Here, F = Force, s = Displacement and $\theta$= Angle between F and s

In the case of the satellite, force of gravity (which acts towards the earth) and displacement are perpendicular to each other.
i.e.,$\theta ={90}^{\circ }.\Rightarrow W=Fscos{90}^{\circ }=0$

Thus, the work done by the force of gravity on the satellite is zero.

Hence, the correct answer is option (d).