1. 2.2 Acceleration
Physics A

2. Objectives I can describe motion in terms of changing velocity.
I can compare graphical representations of accelerated and non-accelerated motions.
I can apply kinematic equations to calculate distance, time or velocity under conditions of constant acceleration.

3. What are the units on acceleration?

4. Tip: Watch for implied data in the problems.
Practice Problem 1
With an average acceleration of -1.2 m/s2, how long will it take a cyclist to bring a bicycle with an initial speed of 6.5 m/s to a complete stop?
Tip: Watch for implied data in the problems.

5. At the bottom of page 50 1, 2, and 3
Conceptual Challenge
At the bottom of page 50 1, 2, and 3

6. Identify which values represent: speeding up, slowing down, constant velocity, speeding up from rest, or remaining at rest.
Table Velocity and Acceleration vi a
Motion + -
- or +

7. Analyze the Following Graph

8. Velocity vs. Time Graph

9. For cases with constant acceleration
𝑣 𝑎𝑣𝑔 = 𝑣 𝑖 − 𝑣 𝑓 2 & 𝑣 𝑎𝑣𝑔 = ∆𝑥 ∆𝑡 Set these two equations equal to one another and solve for Δx.

10. Displacement with Constant Acceleration
∆𝑥= 𝑣 𝑖 − 𝑣 𝑓 ∆𝑡

11. Practice C
1. A car accelerates uniformly from rest to a speed of 6.6 m/s in 6.5 s. Find the distance the car travels during this time.

12. More useful equations:
We know: 𝑎= ∆𝑣 ∆𝑡 = 𝑣 𝑓 − 𝑣 𝑖 ∆𝑡 Solve for 𝑣 𝑓 in terms of a.

13. Velocity with Constant Acceleration
𝑣 𝑓 = 𝑣 𝑖 +𝑎∆𝑡

14. One more…
We know: ∆𝑥= 1 2 𝑣 𝑖 + 𝑣 𝑓 ∆𝑡 & 𝑣 𝑓 = 𝑣 𝑖 +𝑎∆𝑡 Solve for a new Δx.

15. Displacement with Constant Acceleration
∆𝑥= 𝑣 𝑖 ∆𝑡+ 1 2 𝑎 ∆𝑡 2

16. Practice D
Do problems 1-4

17. Final Velocity after any Displacement
vf2 = vi2 + 2aΔx

18. Practice E
Problems 2 & 4

19. Equations for Constantly Accelerating 1-D Motion
∆𝑥= 𝑣 𝑖 − 𝑣 𝑓
𝑣 𝑓 = 𝑣 𝑖 +𝑎∆𝑡
∆𝑥= 𝑣 𝑖 ∆𝑡+ 1 2 𝑎 ∆𝑡 2
vf2 = vi2 + 2aΔx