Dependence of intensity of gravitational field \((\mathrm{E})\) of the earth with distance \((\mathrm{r})\) from the centre of the earth is correctly represented by: (where \(\mathrm{R}\) is the radius of the earth)
1. | 2. | ||
3. | 4. |
A body of mass \(m\) is taken from the Earth’s surface to the height equal to twice the radius \((R)\) of the Earth. The change in potential energy of the body will be:
1. | \(\frac{2}{3}mgR\) | 2. | \(3mgR\) |
3. | \(\frac{1}{3}mgR\) | 4. | \(2mgR\) |
1. | \(-\dfrac{8}{3}{G}\) | 2. | \(-\dfrac{4}{3} {G}\) |
3. | \(-4 {G}\) | 4. | \(-{G}\) |
The height at which the weight of a body becomes \(\left ( \frac{1}{16} \right )^\mathrm{th}\) of its weight on the surface of the earth (radius \(R\)) is:
1. \(5R\)
2. \(15R\)
3. \(3R\)
4. \(4R\)
A spherical planet has a mass \(M_p\) and diameter \(D_p\). A particle of mass \(m\) falling freely near the surface of this planet will experience acceleration due to gravity equal to:
1. | \(\dfrac{4GM_pm}{D_p^2}\) | 2. | \(\dfrac{4GM_p}{D_p^2}\) |
3. | \(\dfrac{GM_pm}{D_p^2}\) | 4. | \(\dfrac{GM_p}{D_p^2}\) |
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. \(\frac{6}{\sqrt{2}}\)
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 is:
1.
2.
3.
4.
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:
1. | is greatest at the instant just before the body hits the earth. |
2. | remains constant throughout. |
3. | is greatest at the instant just after the body is projected. |
4. | is greatest at the highest position of the body. |
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 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.
2.
3.
4.