Terminal Velocity Powerpoint
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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