If g is the acceleration due to gravity on the earth's surface, the gain in the potential energy of an object of mass m raised from the surface of earth to a height equal to the radius of the earth R, is 

1. $\frac{1}{2}mgR$

2. 2 mgR

3. mgR

4. $\frac{1}{4}mgR$

Weightlessness experienced while orbiting the earth in a space-ship is the result of:

1. Inertia                        
2. Acceleration
3. Zero gravity
4. Freefall towards the earth

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:

The escape velocity from the earth is about 11 km/second. The escape velocity from a planet having twice the radius and the same mean density as the earth is

1. 22 km/sec                               
2. 11 km/sec
3. 5.5 km/sec                               
4. 15.5 km/sec

What should be the velocity of earth due to rotation about its own axis so that the weight at equator become 3/5 of initial value. Radius of earth on equator is 6400 km

1.  $7.4\times {10}^{-4}$ rad/sac             

2.  6.4$\times {10}^{-4}$ rad/sac

3.  $7.8\times {10}^{-4}$ rad/sac               

4.  8.7$\times {10}^{-4}$ rad/sac 

If g is the acceleration due to gravity at the earth's surface and r is the radius of the earth, the escape velocity for the body to escape out of the earth's gravitational field is:

1. gr                                       

2. $\sqrt{2gr}$

3. g/r                                       

4. r/g

The escape velocity of a projectile from the earth is approximately

1. 11.2 m/sec                            2. 112 km/sec

3. 11.2 km/sec                          4. 11200 km/sec

The escape velocity of a particle of mass m varies as:

1. $m^2$                                   

2. m

3. $m^0$                                   

4. $m^{-1}$

Acceleration due to gravity is ‘g’ on the surface of the earth. The value of acceleration due to gravity at a height of 32 km above earth’s surface is (Radius of the earth = 6400 km)

1. 0.9 g           

2. 0.99 g

3. 0.8 g           

4. 1.01 g

The time period of a simple pendulum on a freely moving artificial satellite is

1. Zero                           

2. 2 sec

3.  3 sec                          

4.  Infinite