Firstly, you could try to draw a "half-parabola" where the value is the time in seconds and the value is the height of the bird. So it would look a bit like the right part of the graph of . Then you try to make an equation that fits the particular curve you get. You can use the y-intercept point (the value of when , that is the initial height), the x-intercept point (the value of when ) and other features of the parabola to model an equation fitting a bird falling from the sky. You must always consider the unit (time in seconds) and the unit (height in ... meters ?).