A Bit About Measurement of Physics?

Question

The Question is:

Assume that the average distance of the sun from the earth is 400 times the average distance of the moon from earth. Now consider a total eclipse of the sun and state conclusion that can be drawn about:

a. The relation between the sun's diameter and the moon's diameter

b. The relative volumes of the sun and the moon

c. Find the angle intercepted at the eye by a dime that just eclipses the full moon and from this experimental result and the given distance between the moon and the earth (=3.80x10^5 km) estimate the diameter of the moon.

Can someone help me to answer these questions? please guys..

Answer 1

a) The sun and the moon both have the same cosine from your view to the center of the eclipse to the edge of both planets.

Cosine theta = radius of the planet/radius of the orbit.

If the radius of the orbit is 400 times longer, then so is the radius(and thus the diameter) of the sun.

b) volume of a sphere= 4/3 pi r^3

If the radius is 400 times larger, then the volume is 400^3 times larger.

400^3= 64,000,000

c) I cant find anything that tells me what the radius of a time is.

Find the radius of a dime.

Measure the radius of the dime. Find the length from your eye to the dime.

cosine of the angle = radius of the dime/distance to the dime.

Now do the comparison;

Cosine of the angele = radius of the moon/3.80 X 10^5 km