5.4 - Newtonian World - Gravitational Fields Flashcards
What is gravity
Universal attractive force between all matter
What do field lines close together mean
The strength of the field
What is G
6.67x10^-11 (on calculator)
What is Kepler’s first law ?
The orbit of a planet is an ellipse, with the sun at one focus
What is Kepler’s second law ?
A line segment joining a planet and a sum sweeps out equal areas during intervals of equal time
What is Kepler’s third law ?
The square of orbital period (T) is proportional to the cube of the average distance (r) from the sun
How do you derive T ^2is proportional to r^3
Put mv^2 / r= GMm/r^2
What are satellites
Objects that orbit other larger objects
What is gravitational potential
The potential energy per kilogram at any point in the field.
0 potential is defined at infinity
What is gravitational potential difference
The difference in the gravitational potentials of 2 points in a gravitational field
What is gravitational potential energy at a point in the field
The word done per unit mass in moving object with from infinity to that point in the field
What is escape velocity ?
The minimum velocity an object requires in order to escape the gravitational field of an object when projected vertically from its surface (rocket lift off)
What is the escape velocity equation
v = √(2GM/r)
