1 / 30

Measurement

Measurement. Physics is based on measurement. What is the time interval between two clicks of a counter?. What is the temperature of the air?. What is the speed of typhoon?. Measurement. How fast?. How long?. How high?. We start learning physics by learning how to measure……. Time. Time.

avel
Download Presentation

Measurement

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Measurement Physics is based on measurement What is the time interval between two clicks of a counter? What is the temperature of the air? What is the speed of typhoon?

  2. Measurement How fast? How long? How high?

  3. We start learning physics by learning how to measure……..

  4. Time

  5. Time To study motion, we need to find out how quickly an object changes its position.

  6. Besides watches, can you think up other devices which can help us to measure and record the time and motion? Can they measure very short time intervals?

  7. Any other method / device? For example i. by photos

  8. Any other method / device? For example ii. by video

  9. In the laboratory, we use a ticker-tape timer to record the motion

  10. A ticker-tape timer -- is basically a vibrator, -- puts black dots on a tape

  11. Experiment The ticker-tape timer

  12. 1. Set up the ticker-tape timer. 2. Put a length of paper tape through it under the carbon paper disc. 3. Slowly pull the tape for about 5 s (record with stop watch) 4. Count the number of ticks on the tape 5. Calculate the time interval for 1 tick,

  13. For example In 5 s, 245 ticks are marked. Number of ticks per second = 245 /5 = 49 There are 246 dots marked on the tape for 5 s. How many ticks do the timer make in 1 second?

  14. A ticker-tape timer -- is basically a vibrator, -- puts black dots on a tape at the rate of 50 ticks per second, 50Hz

  15. A ticker-tape timer -- is basically a vibrator, -- puts black dots on a tape at the rate of 50 ticks per second, 50Hz The error is due to 1. A miscount of the dots which are too close together 2. The reaction time in using the stop-watch.

  16. A ticker-tape timer -- is basically a vibrator, -- puts black dots on a tape at the rate of 50 ticks per second, 50Hz What is the time between these two adjacent dots? Time interval between two dots = 1/ 50 s = 0.02 s

  17. The time interval between 2 adjacent dots on the tape is called a ‘tick’ 1 tick = 0.02s Time interval between two dots = 1/ 50 s = 0.02 s

  18. By counting the dots marked on the tape, we can work out the time taken. 4 ticks! Time interval = 0.02s x 4 = 0.08s

  19. Besides, a ticker-tape time can use to record the motion (speed).

  20. Studying motion Analyze a ticker-tape

  21. Constant motion Constant motion Speed increasing Speed decreasing

More Related