Force, expressed in newtons, measures the energy imparted from one object to another when they collide, such as when a foot kicks a soccer ball or a bat hits a baseball. One newton represents the energy needed to accelerate a 1-kilogram mass at the rate of 1 meter per second every second (kg m/s/s). In a force minus time calculation, you graph force on the y-axis.
In an impulse calculation, "time" means the amount of time, in seconds, that force was exerted on the object. In a force minus time calculation, you graph time on the x-axis.
Multiplying the average net force by the number of seconds the force was exerted on the object determines the impulse. This equates to the change in the object's momentum. For example, the force of one newton, for one second, imparts an impulse of 1 kg m/s.
You can calculate the impulse graphically. When you plot force on the Y-axis and time on the X-axis, the impulse is the area beneath the force minus time curve.