Explain this whole scenario in simple words:

If a steady force F acting on an object of mass m increases its velocity from u to v in time delta t, the acceleration a is given by:
a= (v-u)/delta time
Subsituting for a in F= ma,
F= m(v-u)/delta time = mv-mu/delta time
We also have
impulse= F delta time= mv-mu= delta (mv)
where mv is the final momentum, mu is the initial momentum and F deta time is called the impulse.
Since
F delta time= mv-mu= delta(mv)
We can write
F= delta(mv)/delta time= delta p/delta time
and define resultant force F as the change in momentum per unit time:
resultant force= change in momentum/time taken
This is another version of Newtons second law. For some problems it is more useful than F=ma.​