Do Now:
1.
2.
3.
4.
Due Next Class:
U1.HW3.Accel & v-t Graphs
Walk in silently. All (problems 1-7 & 1-4)
Grab a calculator and any papers for today.
Put your homework on the corner of your desk.
If you are displaced 5m behind where you started
over a time of 2 seconds. What is your velocity?
By the end of today, IWBAT…
-Define and calculate acceleration
- Calculate distance and displacement
from a velocity-time graph
Why it matters in LIFE:
Part of being a
functional human
being is being able to
understand what’s
happening in the world
around you!
Why it matters in THIS CLASS:
Our Goal = 80%
Mastering today’s lesson (focused
participation, asking questions, etc)
is the first brick that will help us
reach our goal for this unit, and
eventually for the year
TEKS:
4(B) describe and analyze motion in
one dimension using equations with
the concepts of distance,
displacement, speed, average
velocity, instantaneous velocity, and
acceleration;
By the end of today, IWBAT…
-Define and calculate acceleration
- Calculate distance and
displacement from a velocity-time
graph
Topic:
Acceleration & v-t
Graphs
MASTERY QUIZ NEXT CLASS
Definitions, variables, units, and problems
-Distance, d
-Displacement, Δd
-Velocity, vavg
-Acceleration, a
-Kinematic Equations
ACCELERATION, a (Units m/s2)
How velocity changes over time.
∆𝑣
𝑎=
∆𝑡
or
𝑣𝑓 − 𝑣𝑖
𝑎=
∆𝑡
Where:
a = acceleration (m/s2)
v = velocity (m/s)
∆t = time (s)
+v
-v
+a
-a
Speeding up!
+v
-v
-a
+a
Slowing down!
*deceleration means that you are slowing down, not
necessarily that acceleration is negative
EXAMPLE
Describe the motion!
YOU TRY
Describe the motion!
LAST CLASS’ EXAMPLE
What was Sadness’ velocity at time t = 6s?
What was her velocity at time t = 9s?
Build a velocity-time graph.
Position vs. Time
0
0
2
6
7
6
10
0
8
Position (m)
Position (m)
6
4
2
0
0
1
2
3
4
5
6
7
8
9
10
11
7
8
9
10
11
Time (s)
Velocity (m/s)
4
3
Velocity (m/s)
Time (s)
2
1
0
-1
0
1
2
3
4
5
6
-2
-3
Time (s)
EXAMPLE
2
1
3
4
Δd = A1 + A2 + A3 + A4 + A5 + A6
Δd = ½(2)(2) + (6)(2) + ½(2)(2) - ½(2)(2) - (2)(2) - ½(2)(2)
Δd = 8m
5
6
VELOCITY-TIME GRAPHS
Distance is found by adding up the areas under the curve as positives
Displacement is found by adding the areas above the x-axis and
subtracting those below
Velocity is found on the y-axis
Acceleration is found by the slope
a = 3/2
2
3
VELOCITY-TIME GRAPHS PRACTICE
1. Describe the motion on each segment of
the graph.
2. Distance traveled from t = 2s to t =4s
3. Displacement from t = 2s to t = 4s
4. Velocity at time t = 3.5s
5. Acceleration at t = 1s
6.
distance
and displacement
over the
2. Total
d = 1(10)
+ ½(1)(10)
= 15m
6s. + ½(1)(10) = 15m
3. entire
Δd = 1(10)
4. 5m/s
5. a = m = 10/1.5 = 6.67m/s2
6. d = ½(1.5)(10) + 1(10) + ½(1)(10) + ½(1)(10) + 1(10) = 42.5m
Δd = ½(1.5)(10) + 1(10) + ½(1)(10) - ½(1)(10) - 1(10) = 12.5m
EXAMPLE
Formula Rossa, the fastest steel roller
coaster in the world, can go from rest to 240
km/hr in 4.9 seconds. What is its
acceleration?
NOW YOU TRY…
A lion starts from rest and reaches a
final velocity of 13 m/s in 9 seconds.
What is the lion’s acceleration?
EXAMPLE
A car with an initial speed of 23.7 km/s
decelerates at a uniform rate of 0.92 km/s2 for
3.6 s. Find the final speed of the car during this
time.
INDEPENDENT PRACTICE!
Procedure for IP time:
1)
Silent work time
2) Try and solve without notes first!
Hierarchy of who to ask
1) Your brain
2) Your notes
3) Your partner (quiet whisper)
4) Ms. Kelly
EXIT TICKET (5 MIN)
1.Describe the object’s motion on each segment of the
1. A train
travels on a straight path at 32.0 meters per
graph
.
second. It decelerates uniformly to a speed of 14.0
meters per second in 11.0 seconds. What is the train’s
acceleration?
2.From rest, a car accelerates to a final velocity of 26 m/s.
It takes 2s. What is car’s acceleration?
SHOW ALL WORK FOLLOWING THE GUESS METHOD.
SWAP AND MARK (GRADED BY: _____)
(= CORRECT,  = INCORRECT)
1. -1.64 m/s2
1. 13 m/s2
*No G.U.E.S.S, no credit!