Parallax and the sizes of bodies
Answers are for parents and teachers.
1
A radar signal returns after 200 s. What is D in km? (c = 300,000 km/s)
30000000
2
Two cities are 500 km apart with an angle difference of 4.5°. Full circle: 500 · 360 : 4.5. How many km? (500 · 3600 : 45)
40000
3
For practice, very roughly: the Sun’s radius is 700,000 km and the Earth’s 7,000 km. What is the ratio?
100
4
Why were transits of Venus so important in the 18th century?
Measured from different places, they allowed the distance to the Sun to be found by parallax.
5
How do we judge distance with two eyes? Link your answer to parallax.
The brain compares the two directions seen by the eyes (a parallax); the difference is larger for nearby objects.