A projectile is fired from the surface of the earth with a velocity of 5 m/s and angle with the horizontal. Another projectile fired from another planet with a velocity of 3 m/s at the same angle follows a trajectory of the projectile fired from the earth. The value of the acceleration due to gravity on the planet (in ms-2) is: (given, g=9.8 ms-2)
1. | 3.5 | 2. | 5.9 |
3. | 16.3 | 4. | 110.8 |
The escape velocity for a rocket from the earth is \(11.2\) km/s. Its value on a planet where the acceleration due to gravity is double that on the earth and the diameter of the planet is twice that of the earth (in km/s) will be:
1. | \(11.2\) | 2. | \(5.6\) |
3. | \(22.4\) | 4. | \(53.6\) |
For the moon to cease as the earth's satellite, its orbital velocity has to be increased by a factor of -
1. | 2 | 2. | \(\sqrt{2}\) |
3. | \(1/\sqrt{2}\) | 4. | 4 |
The height of a point vertically above the earth’s surface, at which the acceleration due to gravity becomes 1% of its value at the surface is: (Radius of the earth = R)
1. 8R
2. 9R
3. 10R
4. 20R
If the density of the earth is increased 4 times and its radius becomes half of what it is, our weight will be:
1. four times the present value
2. doubled
3. the same
4. Halved
The escape velocity for the Earth is taken \(v_d\). Then, the escape velocity for a planet whose radius is four times and the density is nine times that of the earth, is:
1. | \(36v_d\) | 2. | \(12v_d\) |
3. | \(6v_d\) | 4. | \(20v_d\) |
The value of ‘g’ at a particular point is . Suppose the earth suddenly shrinks uniformly to half its present size without losing any mass then value of ‘g’ at the same point will now become: (assuming that the distance of the point from the centre of the earth does not shrink)
1. | 4.9 m / sec2 | 2. | 3.1 m / sec2 |
3. | 9.8 m / sec2 | 4. | 19.6 m / sec2 |
If both the mass and the radius of the earth is decreased by 1%, then the value of the acceleration due to gravity will:
1. | decrease by 1% | 2. | increase by 1% |
3. | increase by 2% | 4. | remain unchanged |
The change in the potential energy, when a body of mass m is raised to a height nR from the Earth's surface is: (R = Radius of the Earth)
1.
2. nmgR
3. mgR
4.
A satellite whose mass is m, is revolving in a circular orbit of radius r, around the earth of mass M. Time of revolution of the satellite is:
1.
2.
3.
4.