The terminal velocity of a falling body occurs during free fall when a falling body experiences zero acceleration. This is because of the retarding force known as air resistance. Air resistance exists because air molecules collide into a falling body creating an upward force opposite gravity. This upward force will eventually balance the falling body's weight. It will continue to fall at constant velocity known as the terminal velocity.
Friday, 11 March 2016
Acceleration of free fall
An object that falls through a vacuum is subjected to only one external force, the gravitational force, expressed as theweight of the object. An object that is moving only because of the action of gravity is said to be free falling and its motion is described by Newton's second law of motion. With algebra we can solve for the acceleration of a free falling object. The acceleration is constant and equal to the gravitational acceleration g which is 9.8 meters per square second at sea level on the Earth. The weight, size, and shape of the object are not a factor in describing a free fall. In a vacuum, a beach ball falls with the same acceleration as an airliner. Knowing the acceleration, we can determine the velocity and location of any free falling object at any time using the following equations.
X = .5 * a * t^2
where a is the acceleration, V is the velocity, and X is the displacement from an initial location. If the object falls through the atmosphere, there is an additional drag force acting on the object and the physics involved with describing the motion of the object is more complex.
5.6 know and use the relationship for pressure difference
pressure difference = height × density × g
p = h ×ρ × g
5.5 understand that the pressure at a point in a gas or liquid which is at rest acts equally in all directions
If you have a gas or liquid, it will be exerting an equal pressure in all directions.
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