03 motion Flashcards
Revolution is
the time it takes for an object to orbit another object
i.e. Earth’s revolution is 365.24 days
Orbit is
the path of one object revolving around another
The shape and size of a planet’s orbit affects
the time it takes to complete a revolution around the sun
The farther a planet from the sun
the longer its orbit.
Mars takes 687 days where Mercury only takes 88
Why do Planets Orbit the Sun?
Because there is a force of attraction between all objects in the Universe with mass known as gravity
The greater the mass of an object
the stronger its gravitational force
Trajectory is
the path of an object through space
Velocity is
an object’s speed and direction of motion
Escape velocity is
the speed an object must travel to escape the gravitational pull of a planet. (If an object is launched at escape velocity, it will leave the planet and not return)
Orbital velocity is
the speed an object must travel to achieve a perfectly circular orbit
Rotation is
the turning of an object around an imaginary axis running through it
i.e. Earth’s rotation is approximately 24 hours
Motion can either be
real or apparent
Apparent motion is
what we see in the night sky. Does not always represent how the observed object is actually moving.
Real motion is
How an object is actually moving.
Retrograde motion is
the movement of a planet from east to west in the sky, rather than its normal motion from west to east
