Due Monday. Ignore the duplicates; that's just for printing double-sided.
HW: Circular Motion I
Friday, January 29, 2010
Wednesday, January 27, 2010
Intro to Circular Motion
Hi all...I'm out sick today, and probably tomorrow. Your assignment is below for Wednesday and Thursday.
At a given rotational speed, how does linear (or tangential) speed change as the distance from the axis changes?
When you whirl a can at the end of a string in a circular path, what is the direction of the force that acts on the can?
If the string that holds a whirling can in its circular path breaks, what causes the can to move in a straight-line path - centripetal force, centrifugal force, or a lack of force? What law of physics supports your answer?
For space habitats spinning at the same rate, what is the relationship between simulated gravity and the radius of the habitat?
Blue Book
Read and take notes on section 4.5 (p.48-50) and all of chapter 9 (p.122-132). Pay attention to bold words, italics, pictures, and diagrams. Then answer these questions on a separate paper to be turned in:
p.56 # 9 &12
p.133 #2, 3, 6, 8, 12, 17
If you finish early, do some more of the Review Problems or Think and Explain problems. I will give extra credit for any extra problems done correctly and answered in complete sentences.
Brown Book
Read and take notes on section 3.5 (p.31-33) and all of chapter 9 (p.119-129). Pay attention to bold words, italics, pictures, and diagrams. Then answer these questions on a separate paper to be turned in:
p.35 # 9 &12
p.129 #2, 3, 4, 5, 9, 15
If you finish early, do some more of the Review Problems or Think and Explain problems. I will give extra credit for any extra problems done correctly and answered in complete sentences.
Does a 2 kilogram rock have twice the mass of a 1 kilogram rock? Twice the inertia? Twice the weight (when weighed in the same location?)
An elephant and a mouse would both have the same weight in gravity-free space. If they were moving toward you with the same speed, would they bump into you with the same effect? Explain.
Does a child on a merry-go-round revolve or rotate around the merry-go-round's axis?
At a given rotational speed, how does linear (or tangential) speed change as the distance from the axis changes?
When you whirl a can at the end of a string in a circular path, what is the direction of the force that acts on the can?
If the string that holds a whirling can in its circular path breaks, what causes the can to move in a straight-line path - centripetal force, centrifugal force, or a lack of force? What law of physics supports your answer?
For space habitats spinning at the same rate, what is the relationship between simulated gravity and the radius of the habitat?
Monday, January 25, 2010
Unit 7 Review Problems: Force and Newton's Laws
The Unit 7 Test is tomorrow, Tuesday 1/26/10. In addition to the questions below, you will be expected to find the net force using a free-body diagram and to identify objects in static equillibrim.
1. Many automobile passengers have suffered neck injuries when struck by cars from behind. How does Newton's first law apply here? How do headrests help to guard against this type of injury?
2. Suppose you place a ball in the middle of a wagon, and then accelerate the wagon forward. Describe the motion of the ball relative to a) the ground and b) the wagon.
3. If an elephant were chasing you, its enormous mass would be most threatening. But if you sigzagged, its mass would be to your advantage. Why?
4. If you are sitting in a bus that is travelling slong a straight, level road at 100 km/h, you are travelling at 100 km/h too.
a. If you hold an apple over your head, how fast is it moving relative to the road? Relative to you?
b. If you drop the apple does it still have the same horizontal motion? Explain.
5. State Newton's second law in words and in the form of an equation.
6. How much support force (Normal force) does a table exert on a book that weighs 15 N when the book is placed on the table? What is the net force on the book in this case?
7. If a loaded truck can accelerate at 1 m/s^2 and loses its load so it is only 3/4 as massive, what acceleration can it attain for the same driving force?
8. A rocket fired from its launching pad not only picks up speed, but its acceleration increases significantly as firing continues. Why is this so? (Hint: About 90% of the mass of a newly fired rocket is fuel.)
9. Your weight is the result of the gravitational force of the earth on your body. What is the corresponding reaction force?
10. If you walk on a log that is floating in the water, the log moves backward. Why?
11. If you step off a ledge, you noticeably accelerate toward the earth because of the gravitational interaction between the earth and you. Does the earth accelerate toward you as well? Explain.
12. If a bicycle and a massive truck have a head-on collision, upon which vehicle is the impast force greater? Which vehicle undergoes the greater change in motion? Explain.
1. Many automobile passengers have suffered neck injuries when struck by cars from behind. How does Newton's first law apply here? How do headrests help to guard against this type of injury?
2. Suppose you place a ball in the middle of a wagon, and then accelerate the wagon forward. Describe the motion of the ball relative to a) the ground and b) the wagon.
3. If an elephant were chasing you, its enormous mass would be most threatening. But if you sigzagged, its mass would be to your advantage. Why?
4. If you are sitting in a bus that is travelling slong a straight, level road at 100 km/h, you are travelling at 100 km/h too.
a. If you hold an apple over your head, how fast is it moving relative to the road? Relative to you?
b. If you drop the apple does it still have the same horizontal motion? Explain.
5. State Newton's second law in words and in the form of an equation.
6. How much support force (Normal force) does a table exert on a book that weighs 15 N when the book is placed on the table? What is the net force on the book in this case?
7. If a loaded truck can accelerate at 1 m/s^2 and loses its load so it is only 3/4 as massive, what acceleration can it attain for the same driving force?
8. A rocket fired from its launching pad not only picks up speed, but its acceleration increases significantly as firing continues. Why is this so? (Hint: About 90% of the mass of a newly fired rocket is fuel.)
9. Your weight is the result of the gravitational force of the earth on your body. What is the corresponding reaction force?
10. If you walk on a log that is floating in the water, the log moves backward. Why?
11. If you step off a ledge, you noticeably accelerate toward the earth because of the gravitational interaction between the earth and you. Does the earth accelerate toward you as well? Explain.
12. If a bicycle and a massive truck have a head-on collision, upon which vehicle is the impast force greater? Which vehicle undergoes the greater change in motion? Explain.
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