AccelerationAcceleration

PhysicsPhysics

1 Dimensional Motion1 Dimensional Motion

Chapter 2 Section 2 – pages 48-Chapter 2 Section 2 – pages 48-5858

AccelerationAcceleration AccelerationAcceleration (a) – the rate of change (a) – the rate of change

of velocity in a given time intervalof velocity in a given time interval

- units = m/s- units = m/s22

- Equation- Equation

a a avgavg = = change in velocitychange in velocity = = Δ VΔ V = = vvff – – vvii

change in timechange in time Δt Δt ttff - t - tii

Acceleration has magnitude and Acceleration has magnitude and directiondirection

Can be positive or negativeCan be positive or negative

***A negative value for acceleration ***A negative value for acceleration does not always mean something is does not always mean something is slowing down! slowing down!

Acceleration has magnitude and Acceleration has magnitude and directiondirection

- Examples: (Table 2-3 page 51)- Examples: (Table 2-3 page 51)

- Speeding up in a positive direction = +a- Speeding up in a positive direction = +a

- Slowing down in a positive direction = -a- Slowing down in a positive direction = -a

- Speeding up in a negative direction = -a- Speeding up in a negative direction = -a

- Slowing down in a negative direction = +a- Slowing down in a negative direction = +a

- Constant velocity in positive or negative- Constant velocity in positive or negative

direction direction a = 0 m/s a = 0 m/s22

Motion with constant accelerationMotion with constant acceleration

Object speeds up or slows down at a Object speeds up or slows down at a uniform rateuniform rate

EquationsEquations

There are 4 motion (kinematic) There are 4 motion (kinematic) equations equations

Δx = ½ (VΔx = ½ (Vii + V + Vff) • Δt) • Δt

VVff = V = Vii + a • Δt + a • Δt

Δx = VΔx = Vii • Δt + ½ a • (Δt) • Δt + ½ a • (Δt)22

VVff22 = V = Vii

22 + 2a • Δx + 2a • Δx

Constant AccelerationConstant Acceleration

Increasing AccelerationIncreasing Acceleration

Acceleration ComparisonAcceleration Comparison

Negative Velocity and Negative Velocity and Positive AccelerationPositive Acceleration

Positive Velocity and Positive Velocity and Positive AccelerationPositive Acceleration

Positive Velocity and Positive Velocity and Negative AccelerationNegative Acceleration

Negative Velocity and Negative Velocity and Negative AccelerationNegative Acceleration

GraphingGraphing

A. Velocity vs. time graphA. Velocity vs. time graph

page 52 figure 2-11page 52 figure 2-11

B. Concept challenge page 50B. Concept challenge page 50

Homework / In class work:Homework / In class work:

p. 49 #1, 4, 5p. 49 #1, 4, 5

p. 53 #1, 3, 4p. 53 #1, 3, 4

p. 55 #1, 3, 4 p. 55 #1, 3, 4

p. 58 #3, 4, 5p. 58 #3, 4, 5