Section 7 part 2- Gravitation Flashcards
What is affected in a gravitational field?
Any mass
What quantity are fields?
Vectors as they have a direction
What do field lines represent?
The direction of force that will act on an object when the object is put in the field
How do you draw a field diagram with a point?
Field lines equally spaced and finishing on the object
State what a field is
A volume of space where a force can act
Describe a gravitational field diagram and what the force is
Attractive force, looks like a negative radial field
Describe how to draw a uniform field
Field lines parallel and equally spaced and hit surface perpendicularly
How can you determine the field strength?
Density of field lines. Higher density = stronger field
What is the acceleration for an object when in free fall?
g, 9.81 ms^-2 when ignoring other forces such as air resistance
Define gravitational potential
Work done per unit mass to move a small object from infinity which is defined as 0, to that point. All gravitational potentials are negative
Why are gravitational potential energies negative?
Infinity is defined as 0 energy, and it takes energy to push out to r=infinity. Field loses energy as you move out, and this energy is normally transferred to kinetic
What is gravitational potential energy?
Work done per unit mass to move from the initial potential energy to the final potential energy
Describe lines of equipotential, and how you would draw them on a diagram
The lines space out as you go away from the centre, proportional to 1/r^2. They trace lines of equal voltage/electric potential and are perpendicular to field lines
What is potential gradient?
The amount of change in potential per unit length
Describe polar orbit
Low earth orbit - Earth rotates around underneath it, it will scan the whole Earth regularly as orbit goes over poles. 90 min orbit
