30 terms

# Physics Chapter 2

#### Terms in this set (...)

Inertia
The property of things to resist changes in motion.
Newton's first law of motion (the law of inertia)
Every object continues in a state of rest or of uniform speed in a straight line unless acted on by a nonzero force.
Force
In the simplest sense, a push or pull.
Net Force
The vector sum of forces that act on an object.
Mechanical equilibrium
The state of an object or system of objects for which there are no changes in motion. In accord with Newton's first law if at rest the state f rest persists. if moving, motion continues without change,
1. Contrast Aristotle's ideas of natural motion or violent motion.
Natural Motion= dependent on the combination of the four elements (earth, water, air, and fire) the object contain.

*the heavier the object the faster it should fall

Violent Motion= resulted from pushing or pulling, it was imposed motion.
2. What class or motion, natural or violent did Aristotle attribute to motion of the moon?
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3. What state of motion did Aristotle attribute to Earth?
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4. What relationship between the Sun and Earth did Copernicus formulate.
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5. What did Galileo discover in his legendary experiment on the leaning tower of Pisa?
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6. What did Galileo discover about moving bodies and force in hus experiments with inclined planes?
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7. What does it mean to say that a moving object has inertia? Give an example.
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8. Is inertia the reason for moving objects maintaining motion or the name given to this property?
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9. Cite Newton's first law of motion.
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10. What is the net force on a cart thart is pulled to the right with 100 pounds and to the left with 30 pounds?
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11. Why do we say that force is vector quantity?
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12. Can fore be expressed in units of pounds and also in units of Newton's?
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13. What is the net force on an object that is pulled with 80 Newton's to the right and 80 newton's to the left.
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14. What is the net force on a bag pulled down by gravity with 18 newtons and pulled upward by a rope with 18 newtons?
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15. What does it mean to say something is in mechanical equilibrium?
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16. State the equilibrium rule in symbolic notation.
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17. Consider a book that weighs 15 N at rest on a flat table. How many newtons of support does the table provde. what is the net force on the book in this case?
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18. When you stand at rest on a bathroom scale, how your weight compare with the support force by the scale?
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19. A Bowling ball at rest is in equilibrium. is the ball in equilibriu, when it moves at constant speed in a straight-line path?
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20. What is the test for whether or not a moving object is in equilibrium?
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21. If you push on a crate with a force of 100 N and it slides at constant velocity, how much is the friction acting on the crate?
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22. What concept was missing in people's mind in the 16th century when they coyldnt believe earth was moving?
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23. A bird sitting in a tree is traveling at 30 km/s relative to the faraway Sun, When the bird drops to the ground below, does it still go 30 km/s, or does this speed become zero?
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24. Stand next to a wall that travels at 30 km/s relative to the sun. With your feet on the ground, you also travel the same 30 km/s. Do you maintain this speed when your feet leave the ground? What concept supports your answer?
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25. What did Aristotle fail to recognize about the rules of nature for objects on earth and in the heavens?
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