1. Using Kinematic Equations

2. Here is a question…
A car initially travelling at 13 ms-1 rolls down a straight slope, accelerating at 0.6 ms-2 for 10 s. How far does the car travel in this time?

3. Five Variables, Five Equations
vi vf d a t

4. Remember - kufss!
known
unknown
formula
substitute
solve

5. Here is a question…
A car initially travelling at 13 ms-1 rolls down a straight slope, accelerating at 0.6 ms-2 for 10 s. How far does the car travel in this time?

6. What are the “known” variables?
Step One – “known”
A car initially travelling at 13 ms-1 rolls down a straight slope, accelerating at 0.6 ms-2 for 10 s. How far does the car travel in this time?
What are the “known” variables?
vi = 13 ms a = 0.6 ms t = 10 s

7. d = ? (to be calculated) vf = x (not needed)
Step Two – “unknown”
A car initially travelling at 13 ms-1 rolls down a straight slope, accelerating at 0.6 ms-2 for 10 s. How far does the car travel in this time?
What are the “unknown” variables?
d = ? (to be calculated) vf = x (not needed)

8. Step Three – “formula”
Which of the five formulae does not include vf (the one not needed) in it?

9. Step Four – “substitute”
vi = 13 ms-1
a = 0.6 ms-2
t = 10 s

10. Step Five – “solve”

11. Here is another question…
A windsurfer initially travelling at 3 ms-1 is accelerated by a strong wind gust, at 0.08 ms-2. What would be the windsurfer’s speed when he has travelled 100 m since the wind gust started?
KUFSS – SHOW ALL WORKING

12. What are the “known” variables?
Step One – “known”
A windsurfer initially travelling at 3 ms-1 is accelerated by a strong wind gust, at 0.08 ms-2. What would be the windsurfer’s speed when he has travelled 100 m since the wind gust started?
What are the “known” variables?

13. What are the “unknown” variables?
Step Two – “unknown”
A windsurfer initially travelling at 3 ms-1 is accelerated by a strong wind gust, at 0.08 ms-2. What would be the windsurfer’s speed when he has travelled 100 m since the wind gust started?
What are the “unknown” variables?

14. Step Three – “formula”
Which formula does not include the unneeded unknown variable?

15. Step Four – “substitute”

16. Step Five – “solve”

17. Try this now:
What time does it take for an airplane to decelerate uniformly from 120 ms-1 to a stop if the distance covered along the runway is 1500 m?

18. Worksheet #5 (Q1, 2 and 3 only)