Four particles each of mass M, are located at the vertices of a square with side L. The

gravitational potential due to this at the centre of the square is

1. $-\sqrt{32}\frac{GM}{L}$                                   

2. $-\sqrt{64}\frac{GM}{L^2}$

3. zero                                             

4. $\sqrt{32}\frac{GM}{L}$

The mass of the moon is $7.34\times {10}^{22}kg$ and the radius is $1.74\times {10}^{6}m$. The value of

gravitation field will be

1. $1.45<mspace\; width="1em"></mspace>N/kg$                               

2. $1.55<mspace\; width="1em"></mspace>N/kg$

3. $1.75<mspace\; width="1em"></mspace>N/kg$                               

4.  $1.62<mspace\; width="1em"></mspace>N/kg$

The centripetal force acting on a satellite orbiting round the earth and the gravitational

force of earth acting on the satellite both equal F. The net force on the satellite is

1. Zero                                  

2. F

3. $F\sqrt{2}$                                 

4. 2 F

Reason of weightlessness in a satellite is:

1. Zero gravity

2. Centre of mass

3. Zero reaction force by satellite surface

4. None

Mass M is divided into two parts xM and $\left(1-x\right)M$ . For a given separation, the value of x

for which the gravitational attraction between the two pieces becomes maximum is

1. $\frac{1}{2}$                                 

2. $\frac{3}{5}$

3. 1                                   

4. 2

If earth is supposed to be a sphere of radius R, if $g_{30°}$ is value of acceleration due to gravity at latitude of 30^o and g at the pole, the value of $g-g_{{30}^o}$ is

1. $\frac{1}{4}<mspace\; width="1em"></mspace>{\omega }^{2}R$                      

2. $\frac{3}{4}{\omega }^{2}R$

3. ${\omega }^{2}R$                           

4. $\frac{1}{2}{\omega }^{2}R$

If M the mass of the earth and R its radius, the ratio of the gravitational acceleration and

the gravitational constant is

1. $\frac{R^2}{M}$                       

2. $\frac{M}{R^2}$

3. $M{R}^2$                       

4. $\frac{M}{R}$

Two sphere of mass m and M are situated in air and the gravitational force between them

is F. The space around the masses is now filled with a liquid of specific gravity 3. The

gravitational force will now be

1. F                                        

2. $\frac{F}{3}$  

3. $\frac{F}{9}$                                      

4. 3 F

Earth binds the atmosphere because of:

1. Gravity                                     

2. Oxygen between earth and atmosphere

3. Both 1 and 2

4 None of these

The mass of the earth is 81 times that of the moon and the radius of the earth is 3.5

times that of the moon. The ratio of the acceleration due to gravity at the surface of the

moon to that at the surface of the earth is

1. 0.15           

2. 0.0

3. 1             

4. 6