Gravitational fields Flashcards
What is field strength
Force acting per unit mass
Define gravitational potential at a point.
the work done/energy required in bringing 1 kg/unit mass from infinity to the point
What is gravitational potential?
- The integral of field strength or potential energy/mass
2.The potential energy per unit mass
What is potential energy?
MGH or the integral of force
What is the escape velocity
The minimum velocity an object must have at the surface of the planet to escape the pull of gravity using its own kinetic energy.
What is the escape velocity equation?
V^2 = 2GM/R
What is the relationship between the size of orbit and the speed of orbit?
The speed of orbit is faster for small orbits
What is the equation that links the speed of orbit, the circumference, and period of orbit?
v = (2pir)/T
so
T^2 = (4pi^2/GM)r^3
How do use the orbit equation in an eliptical orbit?
Treat r as half the semi-major axis(the longest radius) of the ellipse.
how does potential energy link to potential
potential*mass
How does force relate to potential energy
force = derivative of potential energy
how does field strength relate to force
force = field strength*mass
why is potential negative
energy has to be put in/work has to be done to move mass from inside a field to infinity or a bodies energy
State Newton’s law of gravitation.
The force of attraction between two point masses (or particles)is proportional to product of their masses and inversely proportional to the square of distance between their centres.
What is an alternative formula for gravity?
g = -(change in potential / displacement)
