Topic 8 - Gravity and Orbits

Question 1

what does gravitational field strength depend on?

Answer 1

mass and distance from the body creating the force

Question 2

if the mass of the body is larger, what is the gravitational force?

Answer 2

stronger

Question 3

if the distance to the body is closer, what is the gravitational force?

Answer 3

stronger

Question 4

if a force is stronger, what is it balanced by?

Answer 4

a larger instantaneous velocity

Question 5

objects getting closer to a star or planet do what to remain in orbit?

Answer 5

go faster (increase velocity)

Question 6

if the speed of an object changes whilst in a stable orbit what else much change?

Answer 6

the radius of the orbit

Question 7

what shape are the orbits of moons and planets?

Answer 7

slightly elliptical

Question 8

what shape are comet orbits?

Answer 8

elliptical with the sun near one end of the orbit

Question 9

where does a comet travel fastest?

Answer 9

nearer the sun

Question 10

why do comets speed up?

Answer 10

the increased pull of gravity as it gets closer to the sun

Question 11

what is the formula for orbital speed?

Answer 11

Orbital speed = 2 x π x orbital radius/time period