A body weighs \(200\) N on the surface of the earth. How much will it weigh halfway down the centre of the earth?

1.	\(100\) N	2.	\(150\) N
3.	\(200\) N	4.	\(250\) N

The work done to raise a mass \(m\) from the surface of the earth to a height \(h\), which is equal to the radius of the earth, is:
1. \(\frac{3}{2}mgR\)
2. \(mgR\)
3. \(2mgR\)
4. \(\frac{1}{2}mgR\)

The earth is assumed to be a sphere of radius R. A platform is arranged at a height R from the surface of the earth. The escape velocity of a body from this platform is fv_e, where v_e is its escape velocity from the surface of the earth. The value of f is:

1. $\sqrt{2}$

2. $\frac{1}{\sqrt{2}}$

3. $\frac{1}{3}$

4. $\frac{1}{2}$

Two satellites of Earth, \(S_1\)_, and \(S_2\), are moving in the same orbit. The mass of \(S_1\) is four times the mass of \(S_2\). Which one of the following statements is true?

The figure shows the elliptical orbit of a planet \(m\) about the sun \(\mathrm{S}.\) The shaded area \(\mathrm{SCD}\) is twice the shaded area \(\mathrm{SAB}.\) If \(t_1\) is the time for the planet to move from \(\mathrm{C}\) to \(\mathrm{D}\) and \(t_2\) is the time to move from \(\mathrm{A}\) to \(\mathrm{B},\) then:
           

A particle of mass M is situated at the centre of a spherical shell of the same mass and radius a. The gravitational potential at a point situated at a / 2 distance from the centre, will be:

1. $-\frac{3GM}{a}$

2. $-\frac{2GM}{a}$

3. $-\frac{GM}{a}$

4. $-\frac{4GM}{a}$

The radii of circular orbits of two satellites A and B of the earth are \(4R\) and \(R\) respectively. If the speed of satellite A is \(3v,\) then the speed of satellite B will be:
1. \(3v/4\)
2. \(6v\)
3. \(12v\)
4. \(3v/2\)

A body projected vertically from the earth reaches a height equal to earth’s radius before returning to the earth. The power exerted by the gravitational force:

A planet moving along an elliptical orbit is closest to the sun at a distance r₁ and farthest away at a distance of r₂. If v₁ and v₂ are the linear velocities at these points respectively, then the ratio $\frac{{\mathrm{v}}_1}{{\mathrm{v}}_2}$ is:

1.  ${\mathrm{r}}_2/{\mathrm{r}}_1$

2.  ${\left({\mathrm{r}}_2/{\mathrm{r}}_1\right)}^2$

3.  ${\mathrm{r}}_1/{\mathrm{r}}_2$

4.  ${\left({\mathrm{r}}_1/{\mathrm{r}}_2\right)}^2$

A geostationary satellite is orbiting the earth at a height of \(5R\) above the surface of the earth, \(R\) being the radius of the earth. The time period of another satellite in hours at a height of \(2R\) from the surface of the earth is:
1. \(5\)
2. \(10\)
3. \(6\sqrt2\)
4. \(\frac{6}{\sqrt{2}}\)