Newton’s 2nd Law & the definition of acceleration
ΣF = ma = m(Δv/Δt)
Momentum
p = mv
** Here, you see a car accelerating − or you could say you see a car whose momentum is changing over time. Either statement leads to the conclusion that a net force is acting on the car. In fact, what we call Newton’s second law was expressed by him in terms of a change in momentum, not in terms of acceleration.
ΣF = Δp/Δt