1. MOVEMENT AND CHANGE Measuring acceleration

2. Lesson Aims To test understandings of acceleration To refine your practical skills to provide accurate and reliable acceleration measurements. To be able to understand and interpret velocity-time graphs.

3. Ticker-tape timers

4. Ticker-tape timer The machine vibrates 50 times a second Therefore 10 vibration is 50/10 = 0.2 s

5. Measuring acceleration a = (v – u) t If the trolley is at rest at the start, u = 0 m/s v = d / t

6. Measuring acceleration if we take dots on the ticker tape 51 – 60 how long has the trolley been travelling for? 1.2s

7. Measuring acceleration To find the velocity of the trolley at this time we need to know the distance it travelled as dots 51 – 60 were made. How do we find that out? Easy! It is the length of the tape from dot 51 – 60. We know that it took 0.2s to get from dot 51 to 60 so now we can find the speed

8. Measuring acceleration s = d / t s = / 0.2 s = m / s

9. Measuring acceleration And now we can find the acceleration a = (v – u) t a = = m / s / s

10. Measuring acceleration Height of ramp (cm) Initial speed (m / s) Final speed (m / s) Time taken to get speed (s) Acceleratio n (m/s/s) 50 100 150 200

11. Speed-time graphs Physics text book, p130-131 On the graph paper provided draw an accurate copy of the graph and its annotations off the bottom of p130 Answer Q1 & 2 on p131, complete this for HW. You will need graph paper. Hand in next lesson.