If distance between centres of Earth and Moon is D and mass of Earth is 81, times that of Moon. At w

English

Gujarati

Hindi

7.Gravitation

normal

If the distance between the centres of Earth and Moon is $D$ and mass of Earth is $81\, times$ that of Moon. At what distance from the centre of Earth gravitational field will be zero?

A

$\frac{D}{2}$

B

$\frac{2D}{3}$

C

$\frac{4D}{5}$

D

$\frac{9D}{10}$

Solution

let distance from earth's centre $=x$

Net gravitational field is zero

$\frac{\mathrm{G} \cdot 81 \mathrm{M}}{\mathrm{x}^{2}}=\frac{\mathrm{GM}}{(\mathrm{D}-\mathrm{x})^{2}}$

$\mathrm{x}=\frac{9}{10} \mathrm{D}$

Standard 11

Physics

Share

Similar Questions

A rocket of mass $M$ is launched vertically from the surface of the earth with an initial speed $V.$ Assuming the radius of the earth to be $R$ and negligible air resistance, the maximum height attained by the rocket above the surface of the earth is

normal

A projectile is projected with velocity $k{v_e}$ in vertically upward direction from the ground into the space. (${v_e}$ is escape velocity and $k < 1)$. If air resistance is considered to be negligible then the maximum height from the centre of earth to which it can go, will be : (R = radius of earth)

normal

In order to shift a body of mass $m$ from a circular orbit of radius $3R$ to a higher radius $5R$ around the earth, the work done is

normal

Which of the following statements are true about acceleration due to gravity?

$(a)\,\,'g'$ decreases in moving away from the centre if $r > R$

$(b)\,\,'g'$ decreases in moving away from the centre if $r < R$

$(c)\,\,'g'$ is zero at the centre of earth

$(d)\,\,'g'$ decreases if earth stops rotating on its axis

normal

A body of mass $m$ falls from a height $R$ above the surface of the earth, where $R$ is the radius of the earth. What is the velocity attained by the body on reaching the ground? (Acceleration due to gravity on the surface of the earth is $g$ )

normal