Astronomy: Discussion Questions
Astronomy 1760-60
Fall 2010
Homework 2 Answers
Short Answer/General Questions: These should have short answers of a few sentences. 1. Explain the difference between speed and velocity and why this is important in acceleration. Give an example where an object is accelerating, but their speed is constant.
Speed: Change in position over time – distance over time Velocity: Change in position and direction over time – distance and direction over time Acceleration: Change in Velocity, so a change in speed, direction or both. Example: A change in direction but not speed would be acceleration around a curve, where speed is constant but the direction changes, which means the velocity changes, which means that acceleration occurs.
2. Why …show more content…
The atmosphere of the Earth reflects back into space a portion of the Sun’s light, so it never reaches the ground. But the atmosphere also helps keep some of the energy closer to the Earth once it does reach the ground. If we didn’t have the atmosphere, would the Earth’s surface be warmer or colder? Why do you think this? I’m not asking that you look up the answer – I want you to think about it and give me your reasoning and justify it. You can use to text book to help, but make sure to reference anything that you use from it in your …show more content…
This means that the Earth may have liquid water at some times (during summer) but not most of the year and not constantly. This would also be the average temperature (meaning that the temperature would be fluctuating around this as many of you thought) but since now the average temperature is 288 K (58 F) it means the average would be almost 60 degrees colder. Many of you noted that there would be far more light and energy reaching the Earth, which is true. But much of it wouldn’t interact with the Earth that much and wouldn’t change the temperature on the surface. This is balanced by the greenhouse effect that happens with an atmosphere, which warms the surface even though it also blocks some light from reaching the surface. This balance would result in a slightly colder Earth, though like some of you guessed, it would still be livable for us today (though likely not for evolving life forms).
4. Do an experiment at home. Hang up a piece of paper at eye level with some lines on it 2 mm apart (you can make your own, or there is one posted on D2L). Walk back until you can just see them as distinct lines and could tell exactly how many there are on the page. This gives you a measure of your angular resolution. How far back did you get from the lines? Average eye sight says you should see them just resolving around 4-5 m. Were you closer or farther? Does this mean you have better than
Fall 2010
Homework 2 Answers
Short Answer/General Questions: These should have short answers of a few sentences. 1. Explain the difference between speed and velocity and why this is important in acceleration. Give an example where an object is accelerating, but their speed is constant.
Speed: Change in position over time – distance over time Velocity: Change in position and direction over time – distance and direction over time Acceleration: Change in Velocity, so a change in speed, direction or both. Example: A change in direction but not speed would be acceleration around a curve, where speed is constant but the direction changes, which means the velocity changes, which means that acceleration occurs.
2. Why …show more content…
The atmosphere of the Earth reflects back into space a portion of the Sun’s light, so it never reaches the ground. But the atmosphere also helps keep some of the energy closer to the Earth once it does reach the ground. If we didn’t have the atmosphere, would the Earth’s surface be warmer or colder? Why do you think this? I’m not asking that you look up the answer – I want you to think about it and give me your reasoning and justify it. You can use to text book to help, but make sure to reference anything that you use from it in your …show more content…
This means that the Earth may have liquid water at some times (during summer) but not most of the year and not constantly. This would also be the average temperature (meaning that the temperature would be fluctuating around this as many of you thought) but since now the average temperature is 288 K (58 F) it means the average would be almost 60 degrees colder. Many of you noted that there would be far more light and energy reaching the Earth, which is true. But much of it wouldn’t interact with the Earth that much and wouldn’t change the temperature on the surface. This is balanced by the greenhouse effect that happens with an atmosphere, which warms the surface even though it also blocks some light from reaching the surface. This balance would result in a slightly colder Earth, though like some of you guessed, it would still be livable for us today (though likely not for evolving life forms).
4. Do an experiment at home. Hang up a piece of paper at eye level with some lines on it 2 mm apart (you can make your own, or there is one posted on D2L). Walk back until you can just see them as distinct lines and could tell exactly how many there are on the page. This gives you a measure of your angular resolution. How far back did you get from the lines? Average eye sight says you should see them just resolving around 4-5 m. Were you closer or farther? Does this mean you have better than