An iron sphere of mass $10 \, kg$ has the same diameter as an aluminium sphere of mass $3.5 \, kg$. Both spheres are dropped simultaneously from a tower. When they are $10 \, m$ above the ground,they have the same

$A$ person can jump higher on the surface of the Moon than on the Earth. Why?

$A$ body weighs $63 \, N$ on the surface of the earth. What is the gravitational force on it due to the earth at a height equal to half the radius of the earth (in $, N$)? (Given: Mass of the earth $= 6 \times 10^{24} \, kg$ and radius of the earth $= 6.4 \times 10^{6} \, m$)

Prove that if a body is thrown vertically upward,the time of ascent is equal to the time of descent.

What is the magnitude of the gravitational force between the earth and a $1 \,kg$ object on its surface (in $,N$)? (Mass of the earth is $6 \times 10^{24} \,kg$ and radius of the earth is $6.4 \times 10^6 \,m$.)

State whether the following statement is True or False:
The value of $g$ is zero at the centre of the earth.