fields and their consequences: gravitational fields

what is a force field?

a force field is a region of space where a body experiences a non-contact force

draw a diagram that represents the earth’s gravitational field

a higher field line density means a [] gravitational field

stronger

what do the field lines look like close to the earth’s surface?

parallel to each other and equally spaced

what is newtons law of gravitation?

F = Gm1m2/r²

what do each of the terms in newton’s law of gravitation represent?

F is the magnitude of the force , G is the gravitational constant, m1 and m2 are masses and r is the distance between the two bodies’ centres

what do you assume about the masses in newton’s law of gravitation?

that they are point masses

which direction will F always be in?

F will always act towards the centre of mass causing the gravitational force

what is gravitational field strength?

the force per unit mass, also describes how strong the force due to gravity is at any point in the gravitational field.

what is the equation for gravitational field strength?

g = F/m

for a radial field, what is the equation for gravitational field strength?

g = GM/r²

where does the equation for gravitational field strength in a radial field derive from?

since F = Gm1m2/r², just substitute this into g = F/m

what is the definition for gravitational potential?

gravitational potential is the amount of energy per unit mass at a point in the field. or the work done per unit mass to get a body from that point in the field to infinity.

what is the equation for gravitational potential?

V = -GM/r

why is the value for V negative?

V is negative because the gravitational potential at infinity is 0, meaning gravitational potential must be negative inside a field.

what keeps planets and satellites in orbit?

gravity

what is the centripetal force acting on a planet/satellite?

gravitational force

how can you find the orbital speed of a satellite/planet?

by equating