Understanding+Concepts

Science HW for November 4th

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Science Write-up In class/HW for Thursday Sept. 10 Pg. 35 2. The friend is wrong, he should say speed instead of velocity. 4. The bear's mass would be to your advantage because he has to stop and zig-zag more mass then you. He has to stop more suddenly then you, giving you time to get away. 9. Because the engine is working on the grounds net force, not thye cars. Therefore, if you want to maintain speed, you need it to continue running. 13. The total tension of each rope = 400N. And if the man is balancing himself in the middle exactly, then that is 250 on both ropes, or 125 on each. 200-125=75 on each rope. meaning that the scaffold weighs 2X each tension (for there are two ropes) meaning the scaffold weighs 150 N. 19. The coin remains in a straight path, because it's inertia is the same as the trains. If, however, the train slows while the coin is in the air, the coin's inertia is more then the trains, making it go slightly forward. If you take a turn while the coin is in the air, the coin will go slightly the opposite way that you turned. Pg. 36 1. A 2. B 3. C 4. B 5. A 6. C 7. A 8. A 9. D 10. C Pg 55 2. Newton's 3rd law is most in effect because if you have a heavy object in your hand, you hit, say, 100N of force on the wall, getting 100N back. However, with an empty hand, you can only hit the wall with 65N, getting 65 back, which doesn't hurt as much. 3. When a car turns into a cube, its mass changes, along with the volume and weight.This is because some things are taken off the car to crush it, leaving less available space inside, and less weight. 5. 8. Neither, because according to Galileo did an experiment and found that no matter how much bigger on e rock is, they both hit the ground and accelerate TOGETHER. 9. gravity is greater, which is the reason she is falling. 13. 14. Pg. 55 1. B 2. B 3. B 4. B 5. D 6. A 7. D 8. A 9. B 10. B HW for Friday, Sept. 4 There are many concepts in Chapter three that relate to the movement of my car. For example, one main concept in the chapter is acceleration. As my car moves, it accelerates, a.k.a. gets faster, until it reaches its terminal velocity. Terminal velocity is the speed in the cars acceleration where it can't go any faster. Hw for Thursday, Sept. 1 I can use the data of my car to view its acceleration by, taking a video and seeing how fast it goes 1 meter. Then, I can see how fast it goes 1/2 a meter. Lets say the meter run was 10 seconds. But a half-a-meter was 5. If this is true, your car has no acceleration, or had already reached its terminal velocity. Keep dividing in half, if 1/4 of the meter was 4 seconds, your car must have accelerated to make a 10 second meter, because 4*4 doesn't equal 10. HW for August 31 14. 450 Newtons, because total, the weight is 850, and 850-400=450. 15. The scale reads half of her weight, because she is adjusting her weight evenly between the two sides. 16. Because he tied the rope to his chair, the rope doesn't break, for the weight is evenly distributed between the two sides of the rope. When, however, he tied the rope to the flagpole, the rope did NOT split the weight evenly, and broke, because it had 200 N on it more than it could hold. HW for August 27 2009 - write and answer questions 4,6, and 7 on Wiki (that's this thingy) 4. Question: What is the name of the property by which objects maintain their states of motion? Answer: Inertia 6. Question: Why do we say velocity is a vector quantity and speed is not? Answer: Because velocity tells us the speed and direction, speed only tells us how fast the object is moving. 7. Question: How can you be both at rest and also moving at 100,000 km/h at the same time? Answer: because all motion is relevant. everything is always moving (according to Newton :) {Lab Science 9 excel HW Roger Zahn graph 1.xlsx} {Roger Zahn Science 9 graph 2.xlsx} {Roger Zahn Science 9 graph 3.xlsx}