3.3 Radial gravitational fields

Question 1

what is the main characteristic of a radial field compared to other types of field

Answer 1

The lines of force become wider apart as they get further away from the center of the earth

Question 2

Why do the equipotential surfaces become further away from each other the further the distance is from the earth

Answer 2

Gravitational potential increases in equal amounts between the dashed lines, and since the gravitational potential decreases the further you get from the earth, the distance between the equipotentials needs to increase so that the gravitational potential is equal between each equipotential surface

Question 3

The gravitational force per unit mass, or the gravitational field strength around the earth is described by the equation…?

Answer 3

g=Fg/m = Gmme/r^2 divided by m so the simplified version is g= Gme/r^2

Question 4

For values greater than 6.4 x 10^3 (the radius of the earth, what is the relationship between g and r

Answer 4

inverse square relationship, g is proportional to 1/r^2

Question 5

Why are the values of g negative

Answer 5

Because r is measured away from the earth but the gravitation field is towards the earth

Question 6

What is the earth’s gravitational field at the center

Answer 6

zero