Circular Motion & Gravitation (Gravitation) Flashcards
* + 10.1 for Gravity (GPE, etc.)
What is “F(g)”
Force of Gravity
What is “g”
Gravitational Field Strength
- Force of Gravity experienced by a point per unit mass
- Force per kg (N*kg^-1)
What extra information can “g” tell us near a planet?
Near the surface of a planet, the Gravitational Field Strength (g) is the ACCELERATION an object would experience
How do Field Lines look like on a Field Diagram?
They all point to how a mass would move (towards the gravity-causing-object)
- they are radial
- At the surface of a planet, they look like straight lines pointing downwards
- the closer the field lines are to each other, the stronger the gravitational field at that point
What is “GPE / E(p)”?
Gravitational Potential Energy
- the energy an object has because of its place in a gravitational field
- Joules (J)
- also equal to the WORK done to move a mass to a certain point
- difference between the GPE of two points = Work needed to move the object from point A to point B
What is “ΔV”?
Gravitational Potential Difference
- work done in moving a UNIT MASS to from two points
- Joules per kg (J*kg^-1)
What are Equipotential lines on a Field Diagram?
Regions where the gravitational field strength is the SAME
- Perpendicular to the “Field Lines”
- the closer the Equipotential Lines are to each other, the faster the field is changing (when the field is strongest)
What is “V”?
Gravitational potential
- Work done per unit mass to move it from INFINITY to a point P
- Value is NEGATIVE b/c measuring from INFINITY
- Only AT infinity is GP Zero
What is the “Potential Gradient”?
How quickly the Potential Energy is changing with Distance
* Just slope calculation (Change in Potential Energy / change in distance)
Define Escape Speed
Speed needed to overcome the gravitational attraction of a planet/mass
* to get to GPE=0 (infinity)
