Plzz explain this

Plzz explain this b'CLl-fØ al-Z (?fyezvrnßlmaoeg

Dear Student

Equation given above is for change in momentum of an object.

Momentum is defined as quantity of motion possessed by a body. It is calculates as product of the mass of the body with the velocity (v) it is moving.

Now, change in momentum means 

$$\begin{gathered} =∆p \\ =∆\left(mv\right) \\ =final momentum of the body - initial momentum of the body \\ =m_2{v}_2 - m_1{v}_1 \\ Now, m is mass of the body which is a cons\tan t for a particular body \\ \Rightarrow m_1 = m_2 =m \\ Therefore, ∆p = m (v_2 - v_1) = m ∆v \end{gathered}$$
Therefore, the equation is valid for all circumstances, because m is constant for a body irrespective of any place and time.