1. Chapter 2: Kinematics 2.1 Uniform Motion 2.2 Instantaneous Velocity
2.3 Finding Position from Velocity
2.4 Motion with Constant Acceleration
2.5 Free Fall
2.6 Motion on an Inclined Plane
2.7* Instantaneous Acceleration

2. Stop to think 2.1 P38
Stop to think 2.2 P44
Stop to think 2.3 P48
Stop to think 2.4 P54
Stop to think 2.5 P61
Example 2.3 P 40
Example 2.4 P 41
Example 2.7 P 45
Example 2.10 P 47
Example 2.14 P 53
Example 2.16 P 56
Example 2.18 P 58

3. Motion in one dimension
Determining the signs of position, velocity and acceleration

4. Motion along a straight line
Can be illustrated by position-versus-time graph:
1 s
2 s
3 s
4 s x
Continuous (smooth) curve
Origin
(x=0) x 10 cm 20 cm 40 cm 70 cm 1 2 3 4
t(s)

5. Position vs time graphs

6. Interpreting a position graph
1.What is the position at t =0min
2.What is the position at t =30min
3.What is the velocity at t = 20min
4.What is the velocity at t = 50min
5. What is the acceleration at t=20min
6. If this is V vs. t graph, and x = 0 km
at t = 0min. What is the position at t = 80 min

7. Finding velocity from position graphically

8. Uniform Motion V(avg)= comstant
The position-vs-graph is a straight line
Vs = ∆s/ ∆t
Sf = Si + Vs ∆t

9. Instantaneous velocity
Using motion diagrams and graphs

10. Stop to think 2.2 Which velocity-versus-time goes with the position –versus-time graph

11. Relating a velocity graph to a position graph
The value of the velocity at
Any time equals the slope of
The position graph T

12. Using calculus to find the velocity
Ex. A particle’s position is given by the function
1.What is particle’s position at t = 2s?
x = -8+6 = -2 m
2. What is the velocity at t = 2s
V|t=2 = -3(2)2+3=-9 m/s

13. Finding position from Velocity

14. Example 2.9 1.Where is particle’s turning point?
2.At what time does the particle reach the origin?

15. Motion with constant acceleration
Definition of acceleration
If set t0=0s, ∆t = t
See page 57

16. Example 2. 13 A rocket sled accelerates at 50m/s2 for 5. 0 s
Example 2.13 A rocket sled accelerates at 50m/s2 for 5.0 s. Coasts for 3.0 s, then deploys a parachute and decelerates at 3.0m/s2 until coming to a halt.
What is the maximum velocity of the rocket sled?
What is the total distance traveled?

17. The apple and feather in this photograph are falling in a vacuum
Two objects dropped from the same height will, if air resistance can be neglected
Hit the ground at the same time and with the same speed

18. Free Fall
g = 9.8m/s2
If we choose the y-axis to point vertically up

19. Example 2.16 A falling rock A rock is released from rest at the top of 100-m-tall building. How long does the rock take to fall to the ground, what is impact velocity?
Y0=100m Y1=0m
Vy0= 0 m/s t0 = 0 s

20. Motion on an inclined plane

21. Instantaneous Acceleration

22. Homework 2.50
A 1000Kg weather rocket is launched straight up. The rocket motor provides a constant acceleration for 16s, then the motor stops. The rocket altitude 20 s after launch is 5100m. You can ignore the air resistance
a) What was the rocket’s acceleration during the first 16 s.
The rocket launched with Vo = 0, after 16 s
b) After motor stops, the acceleration is –g as free fall.
c) The rocket’s speed as it passes through a cloud 5100m above the ground

23. B) Will their separation distance increase, decrease or stay the same
Quiz questions: Two stones are release from rest at certain height one after the other
A) Will the difference in their speed increase, decrease or stay the same
B) Will their separation distance increase, decrease or stay the same