# Physics 2211: - PowerPoint PPT Presentation

Physics 2211:

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Physics 2211:

## Physics 2211:

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##### Presentation Transcript

1. Physics 2211: Hooke’s Law Oscillations

2. Some Vocabulary

3. If not for elastic forces, there would be no (living) bungee jumpers . . .

4. “Galloping Gertie” -- The Tacoma-Narrows Bridge

5. equilibrium length of spring Experimental Fact: Hooke’s Law

6. At what time does the block begin to slip? Block slips when spring force on block exceeds maximum static friction force

7. At what time does the block begin to slip? Block slips when spring force on block exceeds maximum static friction force

8. F What force F holds the box at rest if it is displaced a distance X?

9. 2nd Newton Law Try this solution

10. 2nd Newton Law Try this solution Analogous to circular motion

11. Problem A baseball is hit at ground level with an initial velocity of 45 m/s at an angle of 30deg above the horizontal. After achieving its maximum height above ground level the baseball just clears a 10 meter high wall. How far is the wall horizontally from the point where the baseball is hit? (a) 20 m (b) 250 m (c) 160 m (d) 320 m (e) 120 m

12. problem Problem 2. An airplane has a cruising speed of 150 mi/h in calm air. The pilot finds that if he sets a compass heading of 10 south of east, it takes him 20 min to fly to a point that is 60 mi due east of his starting point. If east is assumed to be in the positive x direction (and north in the positive y direction), what is the direction of the wind? (a) 39 (b) 54 (c) 49 (d) 44 (e) 30

13. problem Problem 3. A mass m attached to the end of a string swings in a vertical circle having a radius of R. At an instant when the string makes an angle of a degrees below the horizontal, the speed of the mass is v. What is the tension in the string at this instant?