Terminal Velocity Powerpoint

Contributed by:
Caroline
Explaining the concept of terminal velocity and the forces acting on an object in free fall.
Terminal velocity is defined as the highest velocity attained by an object falling through a fluid. It is observed when the sum of the drag forces is equal to the downward gravity force acting on the object.
1. Terminal Velocity
Gravitational force v Upthrust
2. Gravitational Acceleration
• Gravitational acceleration is the acceleration of an object in free fall
within a vacuum ( and thus without experiencing drag/upthrust ) due
to the force of gravity.
• On earth, the acceleration due to gravity is 9.81 m/s^-2
• F = ma
• Theoretically, an object would keep accelerating and increasing in
velocity as it falls towards the earth BUT real life is not a vacuum and
thus there is a second opposing force known as drag/air resistance
3. The force of Air resistance
• As an object falls, it accelerates, thus its velocity increases
• As the velocity increases however, the downwards force of gravity is
increasingly opposed by the upwards force of air resistance
• The faster the object travels the greater the air resistance
4. The forces on a freefalling object
• As an object falls its velocity increases due to the downwards force of
gravity
• HOWEVER the upwards opposing force of air resistance/drag also
increases as the object gains velocity
• The objects weight ( the downwards force due to gravity) remains
constant as the upthrust increases thus the rate at which the object
gains velocity ( the downwards acceleration decreases).
• This continues until terminal velocity is reached.
5. Terminal velocity
• Terminal velocity is the maximum speed reached by an object in free
fall in a fluid.
• At terminal velocity, the downwards force of gravity (weight) is equal
in magnitude but opposite in direction to the opposing force of air
resistance acting on the object.
• The net force on the falling object is thus 0N as it falls at a constant
speed, thus in equilibrium.
6. Terminal Velocity Graphs