Does velocity or mass impact momentum more and why

As the mass of an object increases the object will be gaining more velocity and the impact of the object would be that the momentum will be very high... also its pretty much common sense bc since the mass of the car is so heavy it makes it more difficult to stop. so for example To understand this think about stopping a car.  If the breaks are applied gently, the momentum of the car is changed gradually over a long period of time and the force on you the passenger is slight.  If you STOMP on the breaks, the momentum of the car changes immediately and the force on the passenger is great. The impulse is the same for the two situations but the time and force are different.