Name:

Unit 3 - Motion

Chapter 9 Acceleration

DAY OUTLINE KEY TERMS1 Ch.8 Homework Booklet Due

Ch.8 TestRead 9.1 summaries p.164-165Assignment:Velocity & Acceleration Wksht

Positive,_Negative_and_Zero_Acceleration2 9.1 Notes 1. Change in velocity

Assignment: p. 391 # 1,3,8,9 2. AccelerationCalculating Change in Velocity Wksht 3. Deceleration

3 9.1 QUIZ 4. Velocity-time graph9.2 Notes (slides 1-5) 5. Constant AccelerationAssignment: p. 405 # 11-13

9.2 Describing Motion Wksht4 9.2 Notes (slides 6-9) 6. Gravity

Assignment: Calculating Acceleration Wksht 7. Acceleration due toAnalyzing Velocity-time Graphs Wksht gravityMotion Match Up Wksht 8. Air resistance

5 Acceleration lab (9-2d) p.402-403 — Due this class

6 Ch.9 Review: Assessment 9.1, 9.2p. 406-407 #4, 6, 7, 11-14, 16-21Physics Unit Wksht

7 Unit 3 Review: p. 413- 417 # 4, 8-12, 14, 18-20, 24-26, 29,31-33, 36-51

9 Chapter 9 package dueUnit 3 Test (Ch. 8+9)

Chapter 9: Acceleration Key TermsKey Term Definition Example/Graphic

1. Change in velocity

2. Acceleration

3. Deceleration

4. VeOocity-time graph

5.Constant Acceleration

6. Gravity

7. Acceleration due togravity

8. Air resistance

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9.1 Describing Acceleration — Student Notes

• An object travelling with

________________________

has equal displacements in equal time intervals.

• An object travelling with non-uniform motion will:

•have different

_____________________________

during equal time intervals.

•take different

_________________________________

to travel equal displacements.

•have

a continuously

______________________________________

Changes in Velocity

• A change in velocity (A) occurs when the_____________________ of an object changes, or its

_______________________________________________

changes, or both.

• A change in

_____________________________

can be calculated by: A = —

• If the change in velocity is

_______________,

the object is travelling with

_________________________

Positive Changes in Velocity

O If the change in velocity is the

______________

(+, -) as the initial ve]locity, the speed of the object is

•Example: A = — = + 9mIs - (+6mIs) = + 3mIs

Negative Changes in Velocity

• If the change in velocity is the

_____________________

(+, -) of the initial velocity, the speed of the

object is

_____________________________

Example: A = 4i — = + 2mIs - (+9mIs) = - 7mIs

Acceleration

• isthe

______________________________________

• the change in

______________________

can be due to a change in

________________________

a change in

_____________________________,

or both.

• two objects with the

___________________________

can have

___________________________

> this is because acceleration describes

________________________________________________

• Example: Suppose both of these vehicles, starting from rest, speed up to 60 km/h. They will have

the

__________________________

but since the dragster can get to 60 km/h faster than the old

car, the

*

-

Positive Acceleration• The is the same as the

. ..

acceleration

velocityp

Example#1:A car

direction.

in the

> If we designate the forward direction as

__________

(+) then the change in velocity is

therefore the acceleration is (+).

Negative Acceleration

• Acceleration that is

_________

of motion is sometimes called

the directionacceleration

velocity..‘ I

Example#1: A car

direction.

in the

> If we designate the forward direction as (+) then the change in velocity is

therefore the acceleration is

Positive and Negative Acceleration

• Example#3: A

___________

> If we designate the backward direction as

velocity is

_____________________________

though the car is increasing its speed.

- in the

_______________________

direction.

_____________________

then the change in

therefore the acceleration is negative (-) even

= —4 mIs mis

- - g4.- I h

positive (+) even though the car is

—v—v =(—lm/s)—

*Remember positive (+) and negative (-) refer to directions.*

—

=(—4m/s)—(—lm/s)=—3m/s =

• Example#4: A

_______________

> If we designate the backward

in the direction.

_________________________as

negative (-) then the

is positive (+), therefore the

_____________________

is

its speed.

Vf —lmIs

(—4 m/s)=+3m/s=

= —4mIs

1

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Name

Use with textbook page 382.

DateApplying

Knowledge

:ec©ir 91

Calculating change in velocity1. Complete the following table by calculating the missing quantities. Positive (+)

represents the forward motion. Use the formula A = — . In the last column,

describe the change in velocity (e.g. object is slowing down, object is speeding up,

or object is in uniform motion).

iZ Description of lsi

+ 14 rn/s + 5 rn/s object is slowing down

+8m/s Orn/s

+25m/s +12m/s

+20m/s —30m/s

—38m/s —lOm/s

—16m/s Om/s

—3m/s +22m/s

Time (s) Velocity (mis)

0 0

10 15

20 28

30 28

40 22

50 12

S

S

S

S

5

2. Use the following data table to calculate the change in velocity for each time interval.

Suppose motion toward north is positive (+).

a)

b)

c)

d)

e)

0s—10

10 s — 20

20s—30

30 s — 40

40 s — 50

© 2008 McGraw-Hill Ryerson Limited Section 9.1 Describing Acceleration • MHR 167

9.2 Calculatin2 Acceleration — Student Notes

Calculating Acceleration:

• The

_______________________

of an object depends on the

__________________________________and

the

______________required

to change the velocity.

When stopping a moving object, the relationship between time and acceleration is:

•

__________________________

the stopping time

__________________________

the acceleration

•

__________________________

the stopping time

__________________________

the acceleration

riseslope i:ii:iSOmIs—25m/s

4.Os—2,Os

— 25 rn/s2.Os

= 13m1s2

I

slope(___________________

acceleration) — object’s velocity is

in the

____________________

direction.

______________

acceleration) — object’s velocity is

___________________

_slope(____________________

acceleration) — object’s velocity is

__________________

direction or the object’s velocity is

Velocity vs. Time

During which time interval was

• The acceleration zero?

• The acceleration negative?

• The acceleration positive?

• The object increasing it’s velocity north?

• The object decreasing it’s velocity north?

• The object moving at a constant velocity north?

Velocity vs. TimeVelocity-Time Graphs:

• The motion of an object with

________________________________

is best represented by a

__________________________

graph.

• The motion of an object with

_________________________________

is best represented by a

___________________________

graph.

• The slope of a velocity-time graph is

______

• is measured in

0

0

50

40

30

20

10

0

.:‘:zzz::: :izi

Time (s)

Determining Motion from a Velocity-Time Graph:

slope (

__________________

in the

increasing in the negative direction.

.

.

.

0

0

E//////\

t2

Time (s)

-.- _A

Calculating Acceleration: a — Av = (a)(At) At—

Example 1: A pooi ball traveling at 2.5 mIs, towards the cushion bounces off at 1.5 mIs. If the ball wasin contact with the cushion for 0.20 s, what is the ball’s acceleration? (Assume towards the cushion isthe positive direction.)

Example 2: A car accelerates from rest at 3.0 mJs2 forward for 5.0 s. What is the velocity of the car atthe end of 5.0 s?

Example 3: A train is travelling east at 14 mIs. How long would to increase its velocity to 22 mIs east,if it accelerated at 0.50 mIs2 east? (assign east direction positive (+)).

More Practice:1. A truck starting from rest accelerates uniformly to 18 mIs [WI in 4.5 s. What is the truck’s

acceleration?

2. A toboggan moving 5.0 mIs forward decelerates backwards at -0.40 mIs2 for 10 s. What is thetoboggan’s velocity at the end of the 10 s?

3. How much time does it take a car, travelling south at 12 mIs, to increase its velocity to 26 mIssouth if it accelerates at 3.5 mJs2 south?

4vekKIty

zo

— vekxty j v&ocydang J: ‘ ncteasg

Gravity and Acceleration: i

Gravityisa_____________

______________that

acts between downii:

•

___________________________________

is a friction-like force that opposes the motion of objectsthat move through the air.

• Ignoring air resistance, all objects will

______________________________

towards the Earth at

Calculating Motion Due to Gravity:Example: Suppose a rock falls from the top of a cliff. What is the change in velocity of the rock after

it has fallen for 1.5 s? (Assign “down” as negative (-))

More Practice:1. What is the change in velocity of a brick that falls for 3.5 s?

2. A ball is thrown straight up into the air at 14 mIs. How long does it take for the ball to slow down toan upward velocity of 6.0 mIs?

3. A rock is thrown downwards with an initial velocity of 8.0 mIs. What is the velocity of the rock after1.5 s?

Name: Block:______ Date:

Science 10 Ch. 9.2 — Describin! Motion Assignment

Example 1: The following position time graph shows an object travelling with uniform motion.

Posution vs Time

UH1Time (s)

The slope of the line is 2.5 mIs. Since the slope is constant, the corresponding velocity time graphwould be a horizontal line drawn at 2.5 mIs.

w 10a,

0

0.0

Li

004.

0 8 10

30

2520

I5

5

002 4 6 8 10

Velocity vs Time

2 4 Time(s)6

1. Describe the motion of the following velocity-time graphs. Include the direction of travel,whether the object is accelerating or decelerating, and any times where the object stops movingaltogether.

a. Slopes:0-4s:

Velocity vs Time

;*0 2 4 6 8

4-6s:

6-8s:

8-lOs:Time (s)

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ApplyingName Date Knowledge

Use with textbook pages 396-400.

Calculating accelerotion1. What is the formula for each of the following quantities?

(a) acceleration (b) change in velocity (c) time interval

2. Complete the following table. Use the motion formula to calculate the missingquantities. Show all your work and use the correct units.

Change in Time Acceleration Formula Used andVelocity Calculation Shown

140m/s 8s 17.5 rn/s2 a==-14——17.5m/szt 8

—60 km/h 4 h

120 km/h 48 km/h2

15s —3.5 rn/s2

12m/s 2.5s

—25 rn/s —12.5 rn/s2

9.6h 5 km/h2

3. Solve each problem using the appropriate motion formula. Show all your work anduse the correct units.

a) A car moving north goes from 5.56 m/s to 63.9 m/s in 7.5 s. What is theacceleration?

b) If a sprinter starts a race and has an acceleration of 2.4 rn/s2 in 2.5 s, what is hisfinal velocity, assuming the initial velocity is 0 m/s2?

c) A rock accelerates at —9.8 m/s2 when falling. How long does it take to change itsvelocity from —4.5 rn/s to —19.4 m/s?

d) A satellite released from a stationary space shuttle accelerates to +68 m/s2 in25 s. What is its change in velocity?

172 MHR • Section 9.2 Calculating Acceleration © 2008 McGraw-Hill Ryerson Limited

AnalyzingName Date Information

Use with textbook pages 394-396.

Analyzing velocity-time graphs1. What is the meaning of each of the following features of a velocity-time graph?

(a) the slope of the line

_______________________________________

(b) a line above the x-axis

_____________________________________

(C) a line below the x-axis

______________________________________

(d) a line with a positive slope

_____________________________________

(e) a line with a negatüve slope

______________________________________

(f) a horizontal section of the graph

________________________________________

(g) a point where the line crosses the x-axis

___________________________________

Use the following velocity-time graph representing the motion of a ball moving tothe right on a table to answer questions 2 and 3.

.10a)>1

Time (s)

2. Complete the following table. Describe the slope, acceleration, and velocity of theball (e.g. positive, negative, or zero).

MOTION OF A BALL

lime Interval Slope I Acceleration Velocity

Os—2s

2s—6s

6s—8s

8s—12s

3. Describe the motion of the ball at each time interval.

(a) 0 s — 2 s

______________________________________

(b) 2 s — 6 s

______________________________________

(c) 6 s — 8 s

______________________________________

(d) 8s—12s

_______________________________

\0 2 foi2

© 2008 McGraw-Hill Ryerson Limited Section 9.2 Calculating Acceleration • MHR 173

DATE: NAME: CLASS:

_______

______

Goal • Review your understanding of terms that describe motion.

Match each statement on the left with the correct term on the right. Write the term’s letter inthe appropriate space. You will not need to use every term.

1.

____

motion with no change in speed or direction A. acceleration

2.

____

a physical quantity that has magnitude but no direction B. acceleration due togravity

3.

____

describes how much an object s position has changed

4.

_____

the total length of a journey that an object takesC. air resistance

D. average acceleration5.

____

describes how fast an object is moving, but not its direction E. average velocity6.

____

difference between initial time and final time F. best-fit line7.

____

the location of an object as seen by an observer G. change in velocity

8.

____

quantity with both magnitude and direction H. constant

9.

_____

friction-like force acceleration

2 I. deceleration10.

____

9.8mJsJ. distance

11.

_____

can be a smooth curve or straight lineK. gravity

12.

_____

allows us to picture or visualize motion L. velocity13.

____

describes the speed and direction of motion M. uniform14.

____

occurs when the speed of an object changes, or its direction N. motion diagramof motion changes, or both o. position

15.

____

acceleration that is opposite to the direction of motion P. position-time graph

16.

_____

the change in an object’s velocity (increase or decrease) in a Q. time

given period of time R. time interval

17.

_____

rate of change in position for a time interval S. scalar

18.

___

when an event occurs T. speed

1 • C 1 U. slope19.

____

me rise or a grapn over its runV. displacement

20.

____

represented by the slope on a velocity-time graphW. vector

X. velocity-time graph

Copyright © 2008, McGraw-Hill Ryerson Limited, a subsidiary of the McGraw-Hill Companies. All rights reserved.This page may be reproduced for classroom use by the purchaser of this book without the written permission of the publisher.

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Physics Unit soo ç0n-j\o CL

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1. (a) A car moves east along a highway at 90.0 km/h for I h and 15 mm. What isthe car’s displacement?

(b) How long will it take for a person walking at 3.8 rn/s north to move 125 m?

2. A car starts from rest and accelerates at a steady rate, reaching a final velocityof 24.0 rn/s in 12s.

(a) Calculate the acceleration of the car.

(b) Calculate the average velocity of the car.

(c) What is the total displacement of the car?

3. A single-engine airplane leaves an airport and flies to another airport 850 kmnorth. It takes 4.0 h to complete the flight. What is the velocity of the airplane?

4. A truck travels from City A due west to City B, a distance of 210 km. The totaltime for the trip is two hours and fifteen minutes. What is the average velocity ofthe truck?

5. A bus travels from City X due east toward City Y. If the bus travels at anaverage velocity of 90 km/h jE], what will be the displacement of the bus 4.5 hlater?

6. How many seconds will it take a speedboat travelling at 70.0 km/h[S] to covera distance of 5.0 km?

7. Donovan Bailey set the world indoor track record in 1996 by running forward50 m in just 5.56 s. What was Bailey’s average velocity?

8. A boat travels across a 450 m lake with an average forward velocity of 5.0rn/s. How much time does it take for this boat to cross the lake?

9. The motion of an elevator is represented by the position-time graph below.Describe, using words, the motion of the elevator during the 30 s time interval.

0-lOs:10-20 s:20-30 s:

Position vs. Time

10. As you approach a town while you are driving, you take your foot off theaccelerator. The car slows down from 90 km/h[Sj to 50 km/h[Sj in 8.0 s. What isthe acceleration of the car?

11. A rock falls from the top of a high cliff. How long would it take this rock toreach a velocity of 25 m/s downward? (Hint: acceleration due to gravity is 9.8m/s2down)

:

U tu 30i i i Tinlie.L(s)...i