Fields Flashcards
The force felt in a force field is a non-contact force. True or False
True
Is force a vector or scalar quantity
Vector
What are some similarities between
electrostatic and gravitational forces
● Inverse square force laws
● Potential concept
● Equipotential surfaces
● Use of field lines
What are some differences between electrostatic and gravitational forces
The gravitational forces from masses always attract, whilst charges may repel or attract
What is gravity
Gravity is the universal attractive force which acts between all matter
What can field lines tell you about a field
The direction of the field and the strength of the field depending on the density of the field lines
What is 𝘨
𝘨 is the force per unit area in a uniform field
In a radial field the magnitude of 𝘨 is the the proportionality constant at that point between force and mass
What is gravitational potential
The work done/energy required in bringing 1 kg/unit mass from infinity to the point
What is the work done by moving a mass in a field
Mass x change in potential
What is the gravitational potential difference
The difference in the gravitational potentials of two points in a gravitational field
What is an equipotential surface
A surface in which every point on the surface has the same potential
How much work is done when you move 1km in any direction on an equipotential
No work is done when moving across equipotentials, as the potential at each point is the same
Why is gravitational potential a negative
value
Work needs to be done to move an object from the inside the field to outside the field. Since outside the field’s potential is defined as 0 then the potential inside the field must be negative
How is the orbital period related to the
radius of a circular orbit
T² ∝ R³
Compare the PE and KE of a lower orbit to a higher one
A lower orbit (smaller m) has less potential energy and more kinetic energy than a higher orbit (bigger r)
