Chapter 13. Gravitational Fields Flashcards
(15 cards)
Define gravitational field
A gravitational field is a region of space where a mass experiences a force.
Define gravitational field strength
The gravitational field strength at a point is defined as the force per unit mass
acting on a small mass placed at that point.
Define gravitational field lines
A gravitational field line is the direction of the gravitational force acting on a
point mass.
What is newton’s law of gravitation
Newton’s law of gravitation states that two point masses attract each other with a
force that is proportional to the product of their masses and inversely proportional
to the square of their separation.
Define gravitational potential
Gravitational potential at a point in a gravitational field is defined as the work
done per unit mass in bringing a small test mass from infinity to the point.
Why is gravitational potential negative?
The gravitational potential at infinity is defined as being zero. The gravitational force is always attractive and so, as the test mass moves from infinity, work can be done by the test mass and as a result its potential decreases. The gravitational potential is negative.
What is a gravitational field?
A gravitational field is a region of space where a mass experiences a force.
Define gravitational field strength at a point and its formula
The gravitational field strength at a point is defined as the force per unit mass acting on a small mass placed at that point. g = F/m
Define a gravitational field line
A gravitational field line is the direction of the gravitational force acting on a point mass.
What is Newton’s law of gravitation?
Two point masses attract each other with a force that is proportional to the product of their masses and inversely proportional to the square of their separation.
Explain what is meant by geostationary orbit
Equatorial orbits in which an object has exactly the same period of rotation as the Earth (24 hours), and moves in the same direction as the Earth (west to east) so that it is always above the same point on the Equator.
Define gravitational potential and its formula
Gravitational potential at a point in a gravitational field is defined as the work done per unit mass in bringing a small test mass from infinity to the point. ɸ = -GM/r
Why is gravitational potential negative?
The gravitational potential at infinity is defined as being zero. The gravitational force is always attractive and so, as the test mass moves from infinity, work can be done by the test mass and as a result its potential decreases.
What is the formula for gravitational potential energy using gravitational potential?
Ep = -Gm1m2/r for two point masses situated r distance apart in a vacuum.
What is the value of the gravitational constant?
6.67 x 10-11 N m2 kg-2
