Gravity Flashcards
What is gravity?
Universal attractive force that acts between all mater
What is a point mass?
One which behaves as if all its mass is concentrated at its centre
Give Newton’s law of universal gravitation for two point masses.
F = (Gm1m2)/r^2
What is a force field?
Region of space in which an object experiences a non-contact force.
Where do gravitational fields exist?
Around all objects with mass.
How can force fields be represented?
vectors using field lines or lines of force on a diagram
What kind of field is the Earth’s gravitational field?
radial overall, but can be considered uniform close to the earths surface
Define the gravitational field strength at any point in a field
g = F/m
Give the field strength for a radial gravitational field at a distance from a point mass.
g = GM/r^2
Define the gravitational potential at a point in a gravitational field.
work done per unit mass to move a small object from infinity to that point
Give the formula for the gravitational potential at a point in a radial field.
V = -GM/r
What is gravitational potential difference?
difference between the gravitational potential at two points in a gravitational field
Give the equation for the work done in moving a mass between two points in a
gravitational field.
(delta)W = m(delta)V
What is an equipotential surface?
surface where the gravitational potential is the same at all points
What is the potential gradient at a point in a field?
(delta)V / (delta)r
