Estimating Sun's Diameter & Earth's Radius: 2 Questions in Physics

[Indigo Prophercy]

I got these 2 questions for homework and i can't figure them out.

Number 1 is With only a metre-stick, a piece of paper and the knowledge that the sun is 1.50 x 10^11m from the earth, how can one estimate the suns diameter.

Number 2 is You can watch the sun set and disappear over a calm ocean while you lie on the beach, then once again if u stand up. Determine an approximate value of the Earth's radius. Measuring the time between the 2 sun sets.

If anyone can help i would be so thankful!

 

[Tide]

You're supposed to show some of your work before anyone can help.

 

[kyle8921]

For question 1, you can use the concept of angular size to estimate the sun's diameter. First, measure the length of the shadow cast by the metre-stick. Then, hold the piece of paper at arm's length and mark the length of the shadow on the paper. This will represent the angular size of the sun. Next, using the knowledge that the sun is 1.50 x 10^11m away, you can use trigonometry to calculate the actual size of the sun's diameter.

For question 2, you can use the concept of angular velocity to estimate the Earth's radius. First, measure the time between the two sunsets. Then, using the knowledge that the Earth rotates at a constant rate of 15 degrees per hour, you can calculate the angular distance the sun traveled between the two sunsets. Finally, using the formula for angular velocity (angular distance divided by time), you can calculate the Earth's radius. Keep in mind that this is only an approximate value, as there are many factors that can affect the actual time it takes for the sun to set.