3.3 Radial Gravitational Fields

Question 1

What is a radial field?

Answer 1

field lines diverge radially outward from a point source or converge radially inwards towards a point source

Question 2

In terms of the gravitational field what direction do the gravitational field lines point to?

Answer 2

The point mass

Question 3

What happens to the equipotentials that are around the mass creating a gravitational radial field.

Answer 3

They get further away from each other as we get further from the middle

Question 4

What is the equation for gravitational field strength in a gravitational radial field?

Answer 4

g = Gm/r^2
where
g = gravitational field strength
G = gravitational constant (6.67x10^-11)
m = mass of thing creating gravitational field
r = separation

Question 5

How do we get this equation?

Answer 5

mixing g = f/m and newton’s law of gravitation

Question 6

If we assume the earth has a uniform density what is the relationship between the gravitational field strength and distance?

Answer 6

They’re directly proportional

Question 7

What about surface and after?

Answer 7

g is inversely proportional to distance ^2

Question 8

If two objects are interacting in each others field by mass is there a point where gravitational field strength is equal to 0?

Answer 8

Yes, at that point G1 + G2 = 0 as fields act in opposite directions

Question 9

What does the graph of g against r look like?

Answer 9

line starting at -9.81 near the negative axis then increases as distance increases (not a straight line but more like a concave curve)