Astrophysics

Question 1

What must their be for any object to be able to orbit another

Answer 1

• A resultant force pointing to the center of the orbit
• Gravitational force between the two objects

Question 2

What orbits the Earth

Answer 2

1. Moon (natural)
2. Satellites (artificial)

Question 3

What orbits the Sun

Answer 3

Planets and comets

Question 4

What shape do planets and moon orbit and what does this result in

Answer 4

Circular
This means their orbital radii remains nearly constant, and their travel at a constant speed

Question 5

What are comets

Answer 5

a combination of rock and ice

Question 6

What shape do comets travel and what does this result in

Answer 6

Elliptical orbit
The radius of the orbit varies and the speed of the comet varies greatly

Question 7

Give a similarity of the orbits of Earth and Halley’s comet

Answer 7

Both orbit the sun

Question 8

Give a difference of the orbits of Earth and Halley’s comet

Answer 8

1. Earth has a constant RADIUS of orbit whereas Halley’s comet has a changing radius
2. Earth travels at a CONSTANT speed whereas Halley’s Comet VARIES its speed
3. Earth travels in a CIRCULAR orbit whereas Halley’s comet travels in an ELLIPTICAL orbit

Question 9

Give the equation for orbital speed

Answer 9

Orbital speed = 2 x pi x orbital radius / time taken

v = 2 x pi x r / T

Question 10

How does the distance from the sun affect the orbital speed

Answer 10

The further away the planets are from the Sun the slower their speed because the gravitational force from the sun decreases the further they are from it

Question 11

What is related to gravitational field strength

Answer 11

Mass and radius

Question 12

How does increased mass affect gravitational field strength

Answer 12

The greater the mass the greater the gravitational field strength

Question 13

In the equation v = 2 x pi x r / T was units are v, r and t in

Answer 13

v= m/s or km/s
r = m or km
t = seconds