d by taking the slope of the position-time graph that makes a straight line.
Investigation: Air Resistance of Falling Coffee Filter
Introduction
Air resistance is the force that opposes the relative motion of an object through a fluid
– liquid or gas. Air resistance is in the opposite direction to the velocity of the object and is
dependent of the velocity. The
air resistance
diminishes the net forces for an object. Air
resistance is also referred to as the drag force and has it has already been experimentally
determined that the drag force is sometimes proportional to the terminal velocity or
sometimes proportional to the terminal velocity squared:
= -
Fdrag
bvT
= -
Fdrag
cvT2
Both constants b and c are drag coefficients that depend on the size of the object. When the
air resistance of an object equals the weight of the object, the net force is zero and no
further acceleration occurs. When the acceleration terminates and the object falls at a
constant velocity the object has reached its
terminal velocity
. A free-falling object
achieves its terminal velocity when the force of gravity (
Fg
) is equal to the drag force
(
)
Fdrag
which causes the overall net force to equal zero.
In the case of free-falling objects the force of gravity is the main force acting on the
object. In addition, to the force of gravity there is an opposite force caused by air resistance
which eventually equals the force of gravity during the objects free-fall. From this we can
deduce that at terminal velocity the drag force acting on the object is equivalent to the
magnitude of the gravitational force on the object,
=
Fdrag
Fg
Hence we will be applying Newton`s second Law to analyze the motion of object under the
influence of gravity and under the dual influence of gravity and air resistance.In this
investigation we will be determining which of the functions best models the drag force of
coffee filters by calculating the air resistance for a coffee filter falling from a fixed.