Estimating the Diameter of the Moon Using a Pencil - Simple Physics Problem

  • Thread starter Thread starter k_yup
  • Start date Start date
AI Thread Summary
To estimate the diameter of the Moon using a pencil, hold the pencil at a distance of about 15 cm from your eye, ensuring its end blocks the Moon. Measure the pencil's diameter, approximately 1.5 cm or 1.5x10^-5 km. Use similar triangle theory to relate the pencil's size and distance to the Moon's size and its distance from Earth, which is 3.8x10^5 km. This method allows for a straightforward calculation of the Moon's diameter based on the measurements taken. This approach effectively combines basic geometry with practical observation.
k_yup
Messages
4
Reaction score
0
im new to the physics world and know this is probably an easy problem but i don't know where to start

Hold a pencil in front of your eye at a position where its end just blocks out the moon. Make approprite measurements to estimate the diameter of the moon, given that the earth-moon distance is 3.8x10^5km.

i figured that you prob had to measure the end of a pencil which i measured about 1.5 cm which is 1.5x10^-5km but i don't really know what to do from there.
 
Physics news on Phys.org
k_yup said:
im new to the physics world and know this is probably an easy problem but i don't know where to start

Hold a pencil in front of your eye at a position where its end just blocks out the moon. Make approprite measurements to estimate the diameter of the moon, given that the earth-moon distance is 3.8x10^5km.

i figured that you prob had to measure the end of a pencil which i measured about 1.5 cm which is 1.5x10^-5km but i don't really know what to do from there.

How far away was the pencil from your eye?
 
about 15cm
 
so use simular triangle theory?
 
k_yup said:
so use simular triangle theory?

Yes, that would do it nicely.

Sorry for late reply I guess I missed it last night when I scanned the board.

Good luck.
 

Thread 'Rolling without slipping on a curved surface'

Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
View full post »

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »

Similar threads

Estimate Diameter of Moon Using Pencil Measurements
Replies
1
Views
2K
Experimenting whether the diameter of a pot affects boiling time for water
Replies
15
Views
2K
Webpage title: Estimating the Diameter of the Moon Using a Total Solar Eclipse
Replies
10
Views
7K
Question about angles and triangles I thinkg
Replies
6
Views
2K
Solve Earth-Moon Mass Estimation Problem - Help Needed!
Replies
9
Views
2K
Time of Fall for a Pencil Dropped at an Angle
Replies
27
Views
5K
Ratio of Sun's Diameter to the Moon's
Replies
2
Views
11K
Why Did Aristarchus Measure the Sun's Distance During a Half Moon?
Replies
7
Views
7K
How does the diameter of a funnel affect the speed of air passing through it?
Replies
6
Views
8K
Physics problem - Momentum and energy
Replies
25
Views
2K

Hot Threads

Recent Insights

Back
Top