The value of $G$ on Earth is $6.67 \times 10^{-11} \ Nm^2/kg^2$. What is the value of $G$ on the Moon?

If the mass of a body is $M$ on the Earth's surface,then the mass of the same body on the Moon's surface is:

Two astronauts are floating in gravitational free space after having lost contact with their spaceship. The two will:

$A$ suitable unit for gravitational constant is

The atmosphere is held to the earth by

Find the acceleration of our galaxy due to the nearest comparably sized galaxy. The approximate mass of each galaxy is $8 \times 10^{11}$ solar masses,and they are separated by $2 \times 10^6$ light-years. Each galaxy has a diameter of $10^5$ light-years. (Assume $1 \text{ light-year} \approx 10^{16} \text{ m}$,gravitational constant $G \approx 10^{-10} \text{ Nm}^2/\text{kg}^2$,and mass of the Sun $= 2.0 \times 10^{30} \text{ kg}$)