D.1 Gravitational fields HL Flashcards
Gravitational Potential Energy
The work done to move a mass from infinity to a point in a gravitational field
Gravitational Potential
The work done per unit mass in bringing a mass from infinity to a point in a gravitational field
How to calculate Work in a Gravitational Field?
To find the work done in moving a mass within a gravitational field, calculate the change in gravitational potential energy
Sign of Gravitational Potential Energy and Potential
Both gravitational potential energy and potential are negative, indicating that work is required to move a mass to infinity from a point within the field.
Gravitational potential energy of a mass m at a point in a gravitational field is the product of its mass and gravitational potential at that point
Equipotential Surfaces
Surfaces over which the gravitational potential is constant. They are always perpendicular to gravitational field lines.
Relationship Between Equipotential Surfaces and Gravitational Field Lines
Equipotential surfaces are perpendicular to gravitational field lines, illustrating the direction of the gravitational force.
Gravitational Potential Gradient
The rate at which gravitational potential changes with distance, indicating the ‘steepness’ of a gravitational field.
Significance of Closely Spaced Equipotential Lines
Indicate areas of stronger gravitational field strength; the closer the lines, the stronger the field.
Equipotential Lines and Energy
Moving along an equipotential surface requires no work since gravitational potential is the same throughout
Orbital Speed
The constant speed that a body must have to maintain a stable orbit around a larger body
Escape Speed
The minimum speed a body needs to break free from the gravitational pull of a larger body without further propulsion
Gravitational Force as Centripetal Force
In orbital motion, the gravitational force between the orbiting bodies provides the necessary centripetal force to keep the satellite in orbit
Principle Behind Kinetic Energy and Escape Velocity
To escape a planet’s gravitational field without further propulsion, an object must have kinetic energy that counterbalances its gravitational potential energy at that location, essentially negating the gravitational pull
Relationship Between Orbital Speed and Radius
Orbital speed decreases as the orbital radius increases, reflecting the inverse square law of gravitational attraction.
