Chapter 2 One-Dimensional Kinematics Dr. Haykel Abdelhamid Elabidi Website:...
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Transcript of Chapter 2 One-Dimensional Kinematics Dr. Haykel Abdelhamid Elabidi Website:...
![Page 1: Chapter 2 One-Dimensional Kinematics Dr. Haykel Abdelhamid Elabidi Website: uqu.edu.sa/staff/ar/4331237 Email: haelabidi@uqu.edu.sa Mobile: 0564518933.](https://reader035.fdocuments.net/reader035/viewer/2022062421/56649db55503460f94aa6774/html5/thumbnails/1.jpg)
Chapter 2One-Dimensional Kinematics
Dr. Haykel Abdelhamid ElabidiWebsite: uqu.edu.sa/staff/ar/4331237
Email: [email protected]
Mobile: 0564518933
4th week of September 2013/DhQ 1434
![Page 2: Chapter 2 One-Dimensional Kinematics Dr. Haykel Abdelhamid Elabidi Website: uqu.edu.sa/staff/ar/4331237 Email: haelabidi@uqu.edu.sa Mobile: 0564518933.](https://reader035.fdocuments.net/reader035/viewer/2022062421/56649db55503460f94aa6774/html5/thumbnails/2.jpg)
Units of Chapter 2
• Position, distance and displacement
• Average speed and velocity
• Instantaneous velocity
• Average and instantaneous acceleration
• Motion with constant acceleration
• Application of the equation of motion
• Freely falling objects
![Page 3: Chapter 2 One-Dimensional Kinematics Dr. Haykel Abdelhamid Elabidi Website: uqu.edu.sa/staff/ar/4331237 Email: haelabidi@uqu.edu.sa Mobile: 0564518933.](https://reader035.fdocuments.net/reader035/viewer/2022062421/56649db55503460f94aa6774/html5/thumbnails/3.jpg)
Position, distance, and displacement
• Kinematics is a part of mechanics that studies the motion of an object without considering the forces acting on it.
Before describing motion, you must set up a coordinate system: define an origin and a positive direction.
![Page 4: Chapter 2 One-Dimensional Kinematics Dr. Haykel Abdelhamid Elabidi Website: uqu.edu.sa/staff/ar/4331237 Email: haelabidi@uqu.edu.sa Mobile: 0564518933.](https://reader035.fdocuments.net/reader035/viewer/2022062421/56649db55503460f94aa6774/html5/thumbnails/4.jpg)
Position, distance, and displacement
The distance is the total length of travel; if you go from your house to the groceries or from the groceries to your house, you cover the same distance of 4.3 mi. Distance is always positive (it is a scalar).
house
friend’s house
![Page 5: Chapter 2 One-Dimensional Kinematics Dr. Haykel Abdelhamid Elabidi Website: uqu.edu.sa/staff/ar/4331237 Email: haelabidi@uqu.edu.sa Mobile: 0564518933.](https://reader035.fdocuments.net/reader035/viewer/2022062421/56649db55503460f94aa6774/html5/thumbnails/5.jpg)
Average speed and velocity
Description of motion needs to consider how rapidly an object moves.
This can be done by introducing the average speed ([L]/[T]):
The average velocity tell us not only how fast an object is moving, it tells us the direction the object is moving.
![Page 6: Chapter 2 One-Dimensional Kinematics Dr. Haykel Abdelhamid Elabidi Website: uqu.edu.sa/staff/ar/4331237 Email: haelabidi@uqu.edu.sa Mobile: 0564518933.](https://reader035.fdocuments.net/reader035/viewer/2022062421/56649db55503460f94aa6774/html5/thumbnails/6.jpg)
calculate the average velocity every 10 mn is better than every 20 mn, every 2 mn is better than every 10 mn and so one. It is desirable to know the velocity at each instant of time.
Instantaneous velocity
The speedometer of your car indicates the instantaneous speed and not the instantaneous velocity.
it can not give information about the direction of motion.
![Page 7: Chapter 2 One-Dimensional Kinematics Dr. Haykel Abdelhamid Elabidi Website: uqu.edu.sa/staff/ar/4331237 Email: haelabidi@uqu.edu.sa Mobile: 0564518933.](https://reader035.fdocuments.net/reader035/viewer/2022062421/56649db55503460f94aa6774/html5/thumbnails/7.jpg)
Average and instantaneous acceleration
The average acceleration is the change in velocity divided by the change in time:
• Velocity and acceleration of an object have the same sign the object accelerates
• Velocity and acceleration of an object have opposit signs the object decelerates
![Page 8: Chapter 2 One-Dimensional Kinematics Dr. Haykel Abdelhamid Elabidi Website: uqu.edu.sa/staff/ar/4331237 Email: haelabidi@uqu.edu.sa Mobile: 0564518933.](https://reader035.fdocuments.net/reader035/viewer/2022062421/56649db55503460f94aa6774/html5/thumbnails/8.jpg)
Average and instantaneous acceleration
Exercise 2-1 p27 (modified):
a) A car goes from 0 to 60.0 mi/h in 6.2 s. What is the average acceleration of this car in m/s2?b) An airplane has an average acceleration of 5.6 m/s2 during takeoff. How long does it take for the plane to reach a speed of 65 m/s? (1 mi=1609 m)
![Page 9: Chapter 2 One-Dimensional Kinematics Dr. Haykel Abdelhamid Elabidi Website: uqu.edu.sa/staff/ar/4331237 Email: haelabidi@uqu.edu.sa Mobile: 0564518933.](https://reader035.fdocuments.net/reader035/viewer/2022062421/56649db55503460f94aa6774/html5/thumbnails/9.jpg)
Motion with constant acceleration
Goal: Give the different equations for motion with constant acceleration and apply them.
![Page 10: Chapter 2 One-Dimensional Kinematics Dr. Haykel Abdelhamid Elabidi Website: uqu.edu.sa/staff/ar/4331237 Email: haelabidi@uqu.edu.sa Mobile: 0564518933.](https://reader035.fdocuments.net/reader035/viewer/2022062421/56649db55503460f94aa6774/html5/thumbnails/10.jpg)
Motion with constant accelerationExample 2-5 p32 (modified):
A boat moves slowly with a constant speed of 1.50 m/s. After, it accelerates at 2.40 m/s2. a) How fast is the boat moving after accelerating for 5.00 s?
b) How far has the boat traveled in this time?
c) At what time is the boat’s speed equal 10.0 m/s?
![Page 11: Chapter 2 One-Dimensional Kinematics Dr. Haykel Abdelhamid Elabidi Website: uqu.edu.sa/staff/ar/4331237 Email: haelabidi@uqu.edu.sa Mobile: 0564518933.](https://reader035.fdocuments.net/reader035/viewer/2022062421/56649db55503460f94aa6774/html5/thumbnails/11.jpg)
Motion with constant acceleration
Example 2-6 p34:
A drag racer starts from rest and accelerates at 7.40 m/s2. How far has it travaled in 2.00 s?
See also the Example 2-8 page 36
![Page 12: Chapter 2 One-Dimensional Kinematics Dr. Haykel Abdelhamid Elabidi Website: uqu.edu.sa/staff/ar/4331237 Email: haelabidi@uqu.edu.sa Mobile: 0564518933.](https://reader035.fdocuments.net/reader035/viewer/2022062421/56649db55503460f94aa6774/html5/thumbnails/12.jpg)
Freely falling objectsFree fall is the motion of an object subject only to the influence of gravity
positive direction
positive direction
![Page 13: Chapter 2 One-Dimensional Kinematics Dr. Haykel Abdelhamid Elabidi Website: uqu.edu.sa/staff/ar/4331237 Email: haelabidi@uqu.edu.sa Mobile: 0564518933.](https://reader035.fdocuments.net/reader035/viewer/2022062421/56649db55503460f94aa6774/html5/thumbnails/13.jpg)
Example 2.10 p40:
A person steps off the end of a 3.00-m-high diving board and drops to the water below.
(a)How long does it take for the person to reach the water?
(b)What the person’s speed on entering the water?
Solution: (a) t=0,782 s, (b) v=7,67 m/s (from eq 2-7 or 2-12)
Freely falling objects
![Page 14: Chapter 2 One-Dimensional Kinematics Dr. Haykel Abdelhamid Elabidi Website: uqu.edu.sa/staff/ar/4331237 Email: haelabidi@uqu.edu.sa Mobile: 0564518933.](https://reader035.fdocuments.net/reader035/viewer/2022062421/56649db55503460f94aa6774/html5/thumbnails/14.jpg)
Freely falling objects
![Page 15: Chapter 2 One-Dimensional Kinematics Dr. Haykel Abdelhamid Elabidi Website: uqu.edu.sa/staff/ar/4331237 Email: haelabidi@uqu.edu.sa Mobile: 0564518933.](https://reader035.fdocuments.net/reader035/viewer/2022062421/56649db55503460f94aa6774/html5/thumbnails/15.jpg)
Thank you for your attention
See you next time Inchallah
Homework: