2021 p1 Flashcards
(17 cards)
if the mass of the sun and distance between earth and sun were both doubled, what would happen to the gravitational force between them
it would halve
Give one reason for anomoly paths of meteors in observations of meteor showers
it may not be part of this meteor shower
explain how the streaks of light called meteors are caused [2 marks]
entry into earth’s atmosphere
heat and light produced
explain how the appearance of the moon during a lunar eclipse is evidence that the earth has a curved surface
shadow is curved
curvature of shadow is different to curvature of earth
state one reason why it is hard to obtain accurate value of the moon’s diameter using eratosthenes’ method (5 options)
-hard to estimate exact time of contacts
-slow progress of eclipse
-fuzzy edges of shadow regions
-weather conditions
-compound error from diameter of earth
explain the cause of precession [2 marks]
-rotation/wobbling of earth’s polar axis
-complex gravitational forces (/field/‘pulls’) of sun & moon
state why ancient civilisations might have been aware of the effects of precession (using naked eye observations) [1 mark]
(angular) size of movement is large
state one feature of precession that makes ot unlikely that ancient civilisations will have known about precession [1 mark]
(angular) size of movement is slow
what factors must be considered in 6 markers
time, location, repeats, weather/seeing conditions, dark eye adaption
what word must be used to describe high tides in tide questions
buldges
Explain how Brahe was able to make such precise measurements without the use of a telescope
-very large angle scales
-reduces percentage error
explain why predictions of the position of mars in the sky made using a circular orbit are so close to its actual position
planta’ orbits are very nearly circular
mars’ orbit must have a low eccentricity
state the name of the scientist who explained plants’ elliptical orbits are caused by the force of gravity
Newton
Define the term ‘circumpolar’ [2 marks]
always above horizon (never rises or sets)
as earth rotates every day / every 24h
define synodic day
time between sunsets/time between sunrises
how long does it take stars to get from 1 upper transit to the next
23h 58m (sidereal day)
Define lunar distance method
uses cotinuously changing angular distance between moon and other celestial bodies
these distances are compared with tables in a nautical almanac to determine the local time and hence longitdue
