Gravitational Potential Flashcards
Define gravitational potential Calculate the gravitational potential difference between two points Explain where an object would have to be places for it gravitational potential energy to be zero
Define gravitational potential energy
The energy of an object due to it position in a gravitational field
Where must an object be placed for its GPE to be 0 and why?
At infinity because the object would be so far away from the surface that the gravitational force is negligible
Define gravitational potential
The GPE per unit mass of a small test mass at a point in a gravitational field
What is gravitational potential also equal to?
The work done per unit mass to move a small object from infinity to that point
Define equipotentials
Surfaces of constant potential
Why are equipotentials for equal increase of potential spaced further apart?
- GFS is weaker at increasing distance from the surface
- GF is less
- The gain of GPE per metre is less so an object has to travel further for equal increase in potential
Show that gravitational field strength is the negative of the potential gradient
Check photos
When is potential gradient constant?
Where equipotentials show equal changes of potential for equal changes of spacing
What does it mean if potential gradient is constant?
Gravitational field strength is constant and the field is uniform
Why are lines of force perpendicular to the equipotentials?
Because the potential gradient is perpendicular to the equipotentials and therefore GFS and GF
Why must the force applied to move a mass upwards equal the gravitational force?
To maintain constant velocity and balance energy.
An equal force prevents acceleration, while a greater force causes acceleration and changes KE as well as GPE
What happens to a mass moving upwards at constant velocity when an equal force is applied?
The net force remains zero, maintaining constant velocity
What occurs if the applied force is less than the gravitational force?
The mass will decelerate and eventually fall
What is required to change the mass’ direction?
A net force must be created by altering the applied force
What is meant by an object state of motion?
The condition of an object in terms of its velocity and acceleration
- speed and direction
- the rate at which the object’s velocity is changing
