Uniform Circular Motion Satellite Motion Planetary Motion Back to Physics

Uniform circular motion can be described as the motion of an object in a circle at a constant speed. As an object moves in a circle, it is constantly changing its direction. In all instances, the object is moving tangent to the circle. Since the direction of the velocity vector is the same as the direction of the object's motion, the velocity vector is directed tangent to the circle as well An object undergoing uniform circular motion is moving with constant speed; nonetheless, it is accelerating due to its change in direction. The direction of the acceleration is inwards.

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Launch Speed equal to 8000 m/s Projectile orbits Earth - Circular Path

Launch Speed greater than 8000 m/s Projectile orbits Earth - Elliptical Path

An
orbiting satellite is a projectile in the sense that the only force acting upon
an orbiting satellite is the force of gravity. Most Earth satellites are
orbiting at a distance high above the Earth such that forces of air resistance
do not influence their motion Second, a satellite is acted upon by the force of
gravity and this force *does* accelerate it towards the Earth. In the
absence of gravity a satellite would move in a straight line path tangent to the
Earth. In the absence of any forces whatsoever, an object in motion (such as a
satellite) would continue in motion with the same speed and in the same
direction (the law of inertia ). Earth curves approximately 5 meters downward
for every 8000 meters along its horizon In order for a satellite to successfully
orbit the Earth, it must travel a horizontal distance of 8000 meters before
falling a vertical distance of 5 meters. Since a horizontally-launched
projectile falls a vertical distance of 5 meters in its first second of motion,
a orbiting projectile must be launched with a horizontal speed of 8000 m/s. When
launched at this speed, the projectile will fall towards the Earth with a
trajectory which matches the curvature of the Earth As such, the projectile will
fall around the Earth, always accelerating towards it under the influence of
gravity, yet never colliding into it since the Earth is constantly curving at
the same rate. Such a projectile is an orbiting satellite. A cannonball launched
with speeds less than 8000 m/s would eventually fall to the Earth. A cannonball
launched with a speed of 8000 m/s would orbit the Earth in a circular path.
Finally, a cannonball launched with a speed greater than 8000 m/s would orbit
the Earth in an elliptical path

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