Gravitational and Electric fields

Question 1

-what is a force field?
-scalar or vector?

Answer 1

-an area in which an object experiences a non-contact force
-vector

Question 2

what are the similarities between gravitational and electric fields?

Answer 2

1. both follow inverse square law
2. both use fields line
3. both have equipotential surfaces

Question 3

what are the differences between gravitational and electric fields?

Answer 3

1. in gravitational, the force is always attractive whereas in electric, the force can be repulsive too
2. gravitational force is on a mass whereas an electric force is on a charge

Question 4

what is Newton’s law of gravitation?

Answer 4

the magnitude of the gravitational force between two mass is directly proportional to the product of the masses and inversely proportional to the square of the distance between them.

Question 5

what is the equation for gravitational force?

Answer 5

F= Gm₁m₂/r²

Question 6

what are the two types of gravitational fields?

Answer 6

• uniform
• radial

Question 7

what is the gravitational field strength?

Answer 7

the force per unit mass on that point in the field

Question 8

what is the equation for gravitational field strength in a uniform field?

Answer 8

g= F/m

Question 9

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

Answer 9

g=GM/r²

Question 10

what is gravitational potential?

Answer 10

the work done per unit mass to move an object from infinity to that point

Question 11

what is the equation for gravitational potential?

Answer 11

V= -GM/r

Question 12

what are equipotential lines?

Answer 12

points where the potential is constant, i.e no work is done when moving along them

Question 13

what is Kepler’s third law?

Answer 13

the square of the orbital period is directly proportional to the cube of the radius

Question 14

what is the equation for the orbital period?

Answer 14

T²=(4π/GM) x r³

Question 15

what is escape velocity?

Answer 15

the minimum velocity an object must travel at in order to escape the gravitational field

Question 16

what is the equation for escape velocity?

Answer 16

v= √(2GM/r)

Question 17

what is a synchronous orbit?

Answer 17

the orbital period of the satellite is equal to the rotational period of the object that it is orbiting

Question 18

what are geostationary satellites used for and why?

Answer 18

• TV and telephones signals because it is always above the same point on the earth

Question 19

what are the differences between low orbit satellites and geostationary satellites?

Answer 19

• they travel much faster therefore there orbital period is much smaller

Question 20

what are low orbit satellites used for?

Answer 20

-monitoring weather
-scientific observations
-military applications

Question 21

derive Keplers law?

Answer 21

set centripetal force to gravitational force and solve for v and substitute 2πr/T for v. then solve for T

Question 22

what is Coulombs law?

Answer 22

the magnitude of the force between two point charges in a vacuum is directly proportional to the product of their charges and inversely proportional to the square of their separation

Question 23

what is the equation for electric force?

Answer 23

F= Q₁Q₂/4πε₀r²

Question 24

Which magnitude is larger, electrostatic force between subatomic particles or the gravitational force?

Answer 24

electrostatic force

Question 25

what is electric field strength?

Answer 25

the force per unit charge

Question 26

what are the 2 equations for electric field strength in a uniform field?

Answer 26

E= F/Q E= V/d

Question 27

what is the equation for electric field strength in a radial field?

Answer 27

E=Q/4πε₀r²

Question 28

what is the equation for work done in an electric field?

Answer 28

W= QΔV

Question 29

what is the trajectory of moving charged particles entering a uniform electric field at right angles?

Answer 29

the particle will experience an electric force , causing it to accelerate so it follows a parabolic shape

Question 30

what is absolute electric potential?

Answer 30

the potential energy per unit charge of a positive point charge at that point in the field

Question 31

what is the equation for electric potential in a radial field?

Answer 31

V= Q/4πε₀r

Question 32

what is the gradient of a tangent to a potential against distance graph equal to ?

Answer 32

electric field strength at that point

Question 33

what is electric potential difference?

Answer 33

the energy needed to move a unit charge between two points

Question 34

what is the area of an electric field strength against distance graph?

Answer 34

electric potential difference