What is the mass of a stone moving at a speed of
15 meters/second and having a momentum of
7.5 kilogram·meters/second?

Explanation:

Momentum means the ability or tendency of an atom to continue moving.

The relation between momentum, mass and speed or velocity is as follows.

                       p = m × v

where,   p = momentum

             m = mass of object

             v = velocity of object

It is given that speed of stone is 15 m/s, and momentum is 7.5 kg m/s. Therefore, calculate the mass of a stone as follows.

                     p = m × v

                        =

                        = 0.5 kg

Thus, mass of the stone is 0.5 kg.