Topic 7

Question 1

why does our weight vary across planets

Answer 1

• weight is dependant on weight = mass*gravity
• gravitational field strength varies as planets are different size meaning weight varies

Question 2

what is gravitational field strength on earth

Answer 2

10N/kg

Question 3

what does our solar system consist of ?

Answer 3

• the sun (our star)
• planets (mercury, Venus ,earth ,mars, Jupiter ,Saturn, Uranus and Neptune)
• natural statelets ; moon
• dwarf plants
• comets and asteroids

Question 4

name the plantes in order closes to the sun

Answer 4

mercury
venus
earth
mars
jupeter
saturn
uranus
neptune

Question 5

what did Ptolemy suggest abt the universe

Answer 5

the earth was ta the centre [geocentric]

Question 6

what did Copernicus suggest abt the universe

Answer 6

the sun is at the centre and the plants orbit it [helocentric]

Question 7

what did Galileo do to theorised abt the universe

Answer 7

he uses telescope to support theory and suggested that moon orbit the planets

Question 8

describe the orbit of moons , planets, comets and artificial satellites

Answer 8

orbit in elliptical shape

Question 9

explain for a stable orbit , the radius of orbit must change if speed changes

Answer 9

• at higher speed , the object requires greater centripetal force
• for grater centripetal force gravitational force must increase
• this is achieve by the the radius of the orbit being reduces

Question 10

explain how the force of gravity acting on a satellite affects its speed and velocity

Answer 10

• the force can alter its velocity as direction us continuously changing
• it cant cause a change in speed since there is no force component in the diction of motion

Question 11

describe the steady state theory

Answer 11

• the universe has always existed
• but it is expanding and creating matter to counteract the loss in density

Question 12

describe the big bang theory

Answer 12

• universe expanded from a small dense point 14 billions ago

Question 13

what is red shift

Answer 13

increase in the wavelength of light due to the source moving away from observer

Question 14

what does the red shift provide evidence for?

Answer 14

• universe expanding
• big bang theory

Question 15

what does the big bang theory suggest?

Answer 15

• the entire universe started from a small hot and dense region of space

Question 16

compare the observed red shifts from two galaxies one further away from each other

Answer 16

• galaxy that is further away travels faster
• red shift is greater the further away it is

Question 17

Explain how both the Big Bang and Steady State theories of
the origin of the Universe both account for red-shift of galaxies

Answer 17

• the red shift phenomenon says that galaxies are moving away from each other
• this shows expansion

Question 18

what does CMB radiation stand for

Answer 18

cosmic microwave background radiation

Question 19

how does CMB radiation provide further evidence for?

Answer 19

• CMB radiating produced from B.B theory
• big bang theory

Question 20

how does the existence of CMBR support the expansion of universe

Answer 20

• gamma radiation was released in the big bang