MODULE 5 IQ3 Flashcards
who is johannes kepler?
plotted the orbit of Mars. he established three laws of planetary motion
1st kepler law (law of orbit)
planetary orbits are ellipses with the sun at one focus
2nd kepler law (law of areas)
planet moves more quickly when it is closer to the sun
3rd kepler law (law of periods)
square of the period of any planet is proportional to the cube of the semimajor axis of its orbit
3rd keplers law equation
r^3/T^2 = GM/4π^2
Where:
R: orbital radius (m)
T: orbital period (s)
M: mass of central object (kg)
G: gravitational constant (6.67 x 10^-11Nm^2kg^-2)
the constant for keplers law
k = GM/4π^2
universal law of gravitation equation
F = GMm/r^2
where:
G: gravitational constant (6.674 x 10^-11 Nm^2kg^-2)
F: force (N)
M: mass of central planet (kg)
m: mass of orbitting planet (kg)
r: radius between planets (m)
velocity of a circular orbit of a satellite
v = √ GM/r
where:
v: velocity (ms^-1)
G: gravitational constant (6.674 x 10^-11 Nm^2kg^-2)
M: mass of satellite (kg)
r: radius (m)
types of orbits
low earth orbit (LEO), geostationary (GEO)
what is low earth orbit (LEO)
altitude between 200 and 2000km
what is geostationary (GEO)
orbital period = 1 day
inclination = 0
stays over one point of earth all the time
altitude: 35 786 km
what is gravitational potential energy (GPE)
the energy an object has due to its position in a gravitational field
equation for GPE=0
U = -GMm/r
where :
U: GPE (J)
G: gravitational constant (6.674 x 10^-11 Nm^2kg^-2)
M: mass of planet (kg)
m: mass of object (kg)
r: centre to centre distance (m)
what is escape velocity
when the object is launched so fast that occurs at at infinite distance, then it will not return
equation for escape velocity
v(esc) =√2GM/r
where:
v(esc): escape velocity (ms^-1)
G: gravitational constant (6.674 x 10^-11 Nm^2kg^-2)
M:
r: radius
