The factors associated with the motion of an object are: Force,Velocity,Acceleration,and Momentum. Out of these four factors,which one remains constant for all bodies—large or small—undergoing a free fall?

State whether the following statement is True or False:
The acceleration of a body thrown vertically upward is numerically the same as the acceleration of a body falling downward,but opposite in sign.

$A$ ball is thrown vertically upwards with a velocity $u$. Calculate the velocity with which it falls to the earth again.

$A$ stone is dropped from a cliff. Its speed after it has fallen $100 \,m$ is: (in $, m s^{-1}$)

Distinguish between mass and weight of an object. How does the weight of an object change when moving from the equator to the poles? When can the weight of an object be zero?

Two objects of masses $m_1$ and $m_2$ having the same size are dropped simultaneously from heights $h_1$ and $h_2$ respectively. Find out the ratio of time they would take in reaching the ground. Will this ratio remain the same if $(i)$ one of the objects is hollow and the other one is solid and $(ii)$ both of them are hollow,size remaining the same in each case. Give reason.