Where the acceleration is constant, i.e. there's constant force and mass.
e.g. 2 m/s^2 constant acceleration means that the object is steadily increasing by 2m/s every second - the graph of velocity against time with uniform acceleration will always be a straight line, with the slope being the acceleration.
e.g. 2 m/s^2 constant acceleration means that the object is steadily increasing by 2m/s every second - the graph of velocity against time with uniform acceleration will always be a straight line, with the slope being the acceleration.