1/20/2017
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Incredible Skydive
Free fall – motion of an object when ONLY the
force of gravity is acting on it
There is no air resistance in free fall, so free fall
is only possible in a vacuum
Terminal velocity – when the force of gravity
and air resistance are equal, no acceleration
occurs
Once an object achieves terminal velocity no
acceleration occurs.
Crumpled Paper vs Open Paper
• Air resistance – a force that opposes
motion of an object through air
• Air resistance is a type of friction
• The more surface area an object has, the
more air resistance
Bowling Ball vs Feather
• Earth’s gravity accelerates all objects at
9.8m/s2. That means a falling object gets 9.8
m/s faster every second it is falling
• Air resistance can affect the speed of a falling
object.
• Air resistance is a type of friction force that
opposes motion of objects through air
• More surface area means more air resistance
Planetary Orbits – an orbit is a
balance between gravity and inertia
• Inertia – the tendency of an object to
keep doing what it is doing
• Without gravity the planet would fly off
into space
• Without inertia the planet would fall into
the sun
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