In the absence of air resistance all object fall with the same uniform rate of acceleration. In the first part of this experiment you will study the motion of a variety of objects in free fall to establish under which conditions the rate of acceleration is constant, and to determine the value of that acceleration. In the second part of the experiment you will study the motion of falling objects (coffee filters) which rapidly reach terminal velocity. Your task will be to establish a quantitative relationship between the terminal velocity and the mass of an object while keeping other important factors (like surface area) approximately constant.

The main instrument for studying the motion of falling objects is a motion detector connected to a logger pro. This instrument detects the position of an object as a function of time and can be used to obtain a graph of velocity vs time. It is from this graph that you should be able to obtain measurements of acceleration and terminal velocity. For both parts of the experiment fix the motion detector at as high a position as possible and release each object at a distance of about 0.5 m below the motion detector (it cannot reliable detect motion at a distance closer than 0.5 m.

Choose a variety of objects and release them beneath the motion detector. You may need to think carefully about how you release the objects so that the motion detector detects the object and not your hand. For each object obtain a velocity vs time graph and use it to obtain the acceleration of each object. Comment on the nature of the graph and the value of acceleration you obtain for each object. Explain any differences you observe in terms of the properties of the object you drop.

Place a coffee filter on the palm of your hand under the motion detector and release it. With practice the filter should fall vertically downwards. When the motion you obtain is not too erratic measure the terminal velocity of the filter from the velocity vs time graph. Change the number of coffee filters that you drop and repeat the measurement. Continue this procedure until you have enough data. Plot a graph relating terminal velocity and number of filters dropped and use a curve of best fit to establish a quantitative relationship between terminal velocity and the number of coffee filters dropped. State your conclusions.