For 3rd years... specially Sr and Cs

2. A. Lydia de Vega is running around the PSHS oval.

3. B. A golf ball is rolling down an inclined plane.

4. C. A Honda CR-V travels 5 miles east; and then, it stops

5. and travel 2 miles west.

6. D. An apple rises and falls after being thrown straight up

7. from the earth’s surface.

8. (4 points) A Toyota Fortuner, traveling at constant speed, makes two complete laps around a circular track of radius r in a time t. (a) When the Fortuner has traveled its one complete lap, what is the magnitude of its displacement? (b) What is the average speed of the car for two complete laps? (c) What is the average velocity’s magnitude for one complete lap? and (d) two complete laps?

9. (2 points) Joe is driving his car. He is initially driving to the right at constant speed. He sees the green traffic light changes to yellow, so he smoothly steps the brake. (a) Is the magnitude of its velocity greater than, less than, or equal to its initial velocity? What about the direction of its velocity? (b) Is his car accelerating? If yes, where is its acceleration?

11. (6 points) An object is initially moving to the left at constant speed from x=+2.00 m to x=0.00 m for 3.00 s. Then it stops for 1.00 s, reverses its direction and uniformly accelerates back to its initial position for 2.00 s. Sketch the graphs of (a) position-time, (b) velocity-time, and (c) acceleration-time.

12. (2 points) A ball is thrown vertically upward from the surface of the earth. (a) At what point in its path is its acceleration zero? (b) At what point in its path is its velocity zero?

14. (5 points) Suppose an object’s velocity (moving in the same direction) was measured at five different moments as given by the following table:

15. Time, t (s)Velocity, v (m/s)0.00.001.01.002.02.003.03.004.03.00

16. Plot these points in a graph and compute the average velocity of its entire trip.

17. (10 points) A record of travel along a straight path is as follows:

18. Start from rest with a constant acceleration of 1.56 m/s2 for 14.0 s.

20. (1 point) For which one of the following situations will the path length equal the magnitude of the displacement?

21. A. Lydia de Vega is running around the PSHS oval.

22. B. A golf ball is rolling down an inclined plane.

23. C. A Honda CR-V travels 5 miles east; and then, it stops and travel 2 miles west.

24. D. An apple rises and falls after being thrown straight up from the earth’s surface.

25. (4 points) A Toyota Fortuner, traveling at constant speed, makes two complete laps around a circular track of radius r in a time t. (a) When the Fortuner has traveled its one complete lap, what is the magnitude of its displacement? – 0

26. (b) What is the average speed of the car for two complete laps? – 4πrt

27. (c) What is the average velocity’s magnitude for one complete lap? and (d) two complete laps? – 0

28. (2 points) Joe is driving his car. He is initially driving to the right at constant speed. He sees the green traffic light changes to yellow, so he smoothly steps the brake.

29. (a) Is the magnitude of its velocity greater than, less than, or equal to its initial velocity? What about the direction of its velocity?

30. - less than, to the right

31. (b) Is his car accelerating? If yes, where is its acceleration? – to the left

34. (a) At what point in its path is its acceleration zero? – none (acceleration is due to gravitational force in free fall)

35. (b) At what point in its path is its velocity zero? – at its highest point/maximum height

36. PROBLEM SOLVING

37. (5 points) A car has an average speed of 11 m/s during the first 18.0 minutes (1080 s) of a 1.0-hour (3600 s) trip. What must the average speed of car during the last 42.0 minutes (2520 s) of the trip be if the car is to have an average speed of 21 m/s for the entire trip?

38. Illustration:

39. Given:v1=11 m/s- average speed for t1=1080 s

40. t2=2520 s- time to have the average speed v2

42. Time, t (s)Velocity, v (m/s)0.00.001.01.002.02.003.03.004.03.00

44. Start from rest with a constant acceleration of 1.56 m/s2 for 14.0 s.

46. Illustration:

47. Given:vi=25.0 m/s- initial velocity of the ball thrown upward

48. a=g=-9.8 m/s2- acceleration due to gravity

49. vf=0- final velocity/velocity at its highest pointa) Find:d= ?- maximum height/highest point of the ball reached<br />Derivation:vf 2-vi 2=2adsince vf=0then -vi 2=2ad so d=-vi 22g<br />Substitution:d=-25.0 m/s22-9.8 m/s2d=31.9 m<br />b) Find:t= ?- time to reach its maximum height<br />Derivation:vf-vi=atsince vf=0then -vi=at so t=-vig<br />Substitution:d=-25.0 m/s-9.8 m/s2t=2.55 s<br />Sirdq_07/03/2011_0020h<br />