|
1. There are only four fundamental forces in the Universe. When you consider the size and complexity of the Universe, how does the fact there are only four forces change your view about God's wisdom and power?
When people such as Ptolemy put forth a model for planetary motion, what did the model have to predict or be able to explain?
What does the fact that Copernicus' model of the Solar System is the correct model tell you about the nature of Science (When you compare his model to Ptolemy's)?
In order for Copernicus' model to accurately predict the backwards motion of planets, how do the speeds of the planets that are closer to the sun have to compare to the Earth's speed around the sun?
Put the following scientists in chronoligical order: Brahe, Newton, Copernicus, Kepler.
Who spent 20 years recording the positions of the planets?
Who put forth the notion that the Sun is the center of the solar system and not the Earth?
Who developed the three laws of planetary motion?
What can you learn from a person who spends 20 years dedicated to something he feels passionately about, and as a result with no aid of a telescope, recorded data that can barely be improved upon today?
As you think about your future, what things from Brahe would you like your life to emulate?
2. Cite Each of Kepler's three laws and sketch a diagram for the first two and give the equation for the third. First Law
Second Law
Third Law
Use the following information for Venus to show Kepler's Third Law is true based on the constant we came up with in class: Orbital Radius = 1.08(10^11); Period = 224.7 days.
Explain why a circle is a special kind of an ellipse:
What does Kepler's Second Law tell you about the speed of the planet as it orbits the sun? In other words, how does the planet's speed compare to the distance it is from the sun? Use the diagram below to justify your answer: 
3. Briefly describe the method in which Cavendish went about to calculute the constant for Newton's Universal Law of Gravitation. 
Why is this experiment refered to as "weighing the Earth?"
Find the gravitational force the sun exerts on the Earth given the following quantities: Mass of Earth = 5.98(10^24); Mass of Sun = 1.99(10^30); distance between Earth and Sun = 1.49(10^11) meters. (3.6(10^22) N = 8.0(10^21) pounds or 8 sextillion pounds)
What force does the Earth exert on the Sun?
What Law justifies your answer?
A 2.0-kg mass is 1.0 m from a an unknown mass. If the gravitational force between them is 6.67(10^-10) N, find the value of the unknown mass. (5.0 Kg)
From the last problem, find each mass's acceleration. (2.0 Kg: a = 3.3(10^-10) m/s^2; 5.0 Kg: a = 1.2(10^-10) m/s^2)
Because of the inverse square relationship between gravitational force and distance, does gravity get weaker slowly or quickly the farther away you get from the Earth?
Suppose you weighed 150 pounds on the Earth. How much would you weigh if you were located 1.5 times farther away? (67 pounds)
Why would you feel weightless if you were in orbit even though you would still weigh 67 pounds?
For Honors Physics Only: Two identical lead spheres whose centers are 2.0 m apart attract each other with a force of .00001 N. Find the mass of each sphere. (m = 774-kg)
4. The acceleration due to gravity (little g), is 9.8 m/s^2 on the surface of the Earth. You can actually calculate that value by doing the following: since gravitational force is equivalent to your weight, which is found by mass times g, you can set up the following equation:  
The moon is 3.84(10^8) meters (239,000 miles) from the Earth, which is roughly 60 times the Earth’s radius. It makes one complete circle about every 27.3 days (2.36(10^6) seconds). Find the moon’s centripetal acceleration. (.0027 m/s^2)
Now calculate the value of g where the moon is located from the Earth using the equation found in level two. (.0027 m/s^2)
What can you conclude about g and the centripetal acceleration of an orbiting body?
When an object is orbiting a planet, there is a minimum speed necessary for a satellite or moon to maintain a circular (perfect circle) orbit depending on how far away the object is from the planet. If the satellite has a speed smaller than this critical speed, its orbital shape will be elliptical. Draw on the diagram below where you think the Earth would be located if the satellite began its orbit on the left side and was traveling with speed that was less than the critical speed: 
For Honors Physics Only: To find the minimum speed necessary to maintain a circular orbit, one must set the gravitational force equation equal to the centripetal force equation: 
|