1 motion introduction. 2 frozen time 3 4 motion diagram
TRANSCRIPT
1
Motion
Introduction
2
Frozen Time
3
Frozen Time
4
Motion Diagram
5
Motion Diagram
6
Motion Diagrams
7
CO2, Mauna Loa
365
370
375
380
385
390
2000 2001 2002 2003 2004 2005 2006 2007 2008
time (years)
CO
2 C
on
ce
ntr
ati
on
(p
pm
)
Linear Functions
1.Find the equation of the red trend line in the form y=mx+b, where x is years since 2000 and y is concentration of CO2 in ppm.
8
Chapter 1. Reading Quizzes
9
What is a “particle”?
A. Any part of an atomB. An object that can be represented as a mass at
a single point in spaceC. A part of a wholeD. An object that can be represented as a single
point in timeE. An object that has no top or bottom, no front or
back
10
What is a “particle”?
A. Any part of an atomB. An object that can be represented as a mass at
a single point in spaceC. A part of a wholeD. An object that can be represented as a single point
in timeE. An object that has no top or bottom, no front or
back
11
What quantities are shown on a completemotion diagram?
A. The position of the object in each frame of the film, shown as a dot
B. The average velocity vectors (found by connecting each dot in the motion diagram to the next with a vector arrow)
C. The average acceleration vectors (with one acceleration vector linking each two velocity vectors)
D. All of the above
12
What quantities are shown on a completemotion diagram?
A. The position of the object in each frame of the film, shown as a dot
B. The average velocity vectors (found by connecting each dot in the motion diagram to the next with a vector arrow)
C. The average acceleration vectors (with one acceleration vector linking each two velocity vectors)
D. All of the above
13
An acceleration vector
A.tells you how fast an object is going.B.is constructed from two velocity vectors.C.is the second derivative of the position.D.is parallel or opposite to the velocity vector.E.Acceleration vectors weren’t discussed in this
chapter.
14
An acceleration vector
A.tells you how fast an object is going.B.is constructed from two velocity vectors.C.is the second derivative of the position.D.is parallel or opposite to the velocity vector.E.Acceleration vectors weren’t discussed in this
chapter.
15
The pictorial representation of a physics problem consists of
A.a sketch.B.a coordinate system.C.symbols.D.a table of values.E.all of the above.
16
The pictorial representation of a physics problem consists of
A.a sketch.B.a coordinate system.C.symbols.D.a table of values.E.all of the above.
17
Motion Diagram Concept QuestionsMotion Diagram Concept Questions
18
Three motion diagrams are shown. Which is a dust particle settling to the floor at constant speed, which is a ball dropped from the roof of a building, and which is a descending rocket slowing to make a soft landing on Mars?
A. (a) is ball, (b) is dust, (c) is rocket
B. (a) is ball, (b) is rocket, (c) is dust
C. (a) is rocket, (b) is dust, (c) is ball
D. (a) is rocket, (b) is ball, (c) is dust
E. (a) is dust, (b) is ball, (c) is rocket
19
A. (a) is ball, (b) is dust, (c) is rocket
B. (a) is ball, (b) is rocket, (c) is dust
C. (a) is rocket, (b) is dust, (c) is ball
D. (a) is rocket, (b) is ball, (c) is dust
E. (a) is dust, (b) is ball, (c) is rocket
Three motion diagrams are shown. Which is a dust particle settling to the floor at constant speed, which is a ball dropped from the roof of a building, and which is a descending rocket slowing to make a soft landing on Mars?
20
A particle moves from position 1 to position 2 during the interval ∆t. Which vector shows the particle’s average velocity?
21
A particle moves from position 1 to position 2 during the interval ∆t. Which vector shows the particle’s average velocity?
22
A particle undergoes acceleration while moving from point 1 to point 2. Which of the choices shows the velocity vector as the object moves away from point 2?
a
v2
23
A particle undergoes acceleration while moving from point 1 to point 2. Which of the choices shows the velocity vector as the object moves away from point 2?
a
v2
24
Graphical Analysis of Motion Concept QuestionsGraphical Analysis of Motion Concept Questions
25
Which position-versus-time graph represents the motion shown in the motion diagram?
26
Which position-versus-time graph represents the motion shown in the motion diagram?
27
Which velocity-versus-time graph goes with the position-versus-time graph on the left?
28
Which velocity-versus-time graph goes with the position-versus-time graph on the left?
t
x
The graph of position versus The graph of position versus
time for a car is given below. time for a car is given below.
What can you say about the What can you say about the
velocity of the car over time?velocity of the car over time?
a) it speeds up all the time
b) it slows down all the time
c) it moves at constant velocity
d) sometimes it speeds up and
sometimes it slows down
e) not really sure
t
x
The graph of position versus The graph of position versus
time for a car is given below. time for a car is given below.
What can you say about the What can you say about the
velocity of the car over time?velocity of the car over time?
The car moves at a constant velocity
because the x vs. t plot shows a straight
line. The slope of a straight line is
constant. Remember that the slope of x
versus t is the velocity!
a) it speeds up all the time
b) it slows down all the time
c) it moves at constant velocity
d) sometimes it speeds up and
sometimes it slows down
e) not really sure
t
x
a) it speeds up all the time
b) it slows down all the time
c) it moves at constant velocity
d) sometimes it speeds up and
sometimes it slows down
e) not really sure
The graph of position vs. The graph of position vs.
time for a car is given below. time for a car is given below.
What can you say about the What can you say about the
velocity of the car over time?velocity of the car over time?
a) it speeds up all the time
b) it slows down all the time
c) it moves at constant velocity
d) sometimes it speeds up and
sometimes it slows down
e) not really sure
t
The graph of position vs. The graph of position vs.
time for a car is given below. time for a car is given below.
What can you say about the What can you say about the
velocity of the car overvelocity of the car over time? time?
The car slows down all the time
because the slope of the x vs. t graph
is diminishing as time goes on.
Remember that the slope of x vs. t is
the velocity! At large t, the value of the
position x does not change, indicating
that the car must be at rest.
x
33
Which position-versus-time graph goes with the velocity-versus-time graph at the top? The particle’s position at ti = 0 s is xi = –10 m.
34
Which position-versus-time graph goes with the velocity-versus-time graph at the top? The particle’s position at ti = 0 s is xi = –10 m.
Consider the line labeled A Consider the line labeled A
in the in the vv versus versus tt plot. How plot. How
does the does the speedspeed change change
with time for line A?with time for line A?
v
t
A
B
a) decreasesa) decreases
b) increasesb) increases
c) stays constantc) stays constant
d) increases, then decreasesd) increases, then decreases
e) decreases, then increasese) decreases, then increases
Consider the line labeled A Consider the line labeled A
in the in the vv versus versus tt plot. How plot. How
does the does the speed speed change change
with time for line A?with time for line A?
v
t
A
B
a) decreasesa) decreases
b) increasesb) increases
c) stays constantc) stays constant
d) increases, then decreasesd) increases, then decreases
e) decreases, then increasese) decreases, then increases
In case A, the initial velocity is
positive and the magnitude of
the velocity continues to
increase with time.
Consider the line labeled Consider the line labeled
B in the B in the vv versus versus tt plot. plot.
How does the How does the speedspeed
change with time for line change with time for line
B?B?
v
t
A
B
a) decreasesa) decreases
b) increasesb) increases
c) stays constantc) stays constant
d) increases, then decreasesd) increases, then decreases
e) decreases, then increasese) decreases, then increases
Consider the line labeled B Consider the line labeled B
in the in the vv versus versus tt plot. How plot. How
does the does the speed speed change change
with time for line B?with time for line B?
v
t
A
B
a) decreasesa) decreases
b) increasesb) increases
c) stays constantc) stays constant
d) increases, then decreasesd) increases, then decreases
e) decreases, then increasese) decreases, then increases
In case B, the initial velocity is positive
but the magnitude of the velocity
decreases toward zero. After this, the
magnitude increases again, but
becomes negative, indicating that the
object has changed direction.
39
Which velocity-versus-time graph or graphs goes with this acceleration-versus-time graph? The particle is initially moving to the right and eventually to the left.
40
Which velocity-versus-time graph or graphs goes with this acceleration-versus-time graph? The particle is initially moving to the right and eventually to the left.
When throwing a ball straight up, When throwing a ball straight up,
which of the following is true about which of the following is true about
its velocity its velocity vv and its acceleration and its acceleration aa
at the highest point in its path?at the highest point in its path?
a) both a) both v = 0v = 0 and and a = 0a = 0
b) b) v v 0 0, but , but a = 0a = 0
c) c) v = 0v = 0, but , but a a 0 0
d) both d) both v v 00 and and a a 0 0
e) not really suree) not really sure
y At the top, clearly v = 0 because the ball has
momentarily stopped. But the velocity of the
ball is changing, so its acceleration is definitely
not zero! Otherwise it would remain at rest!!
When throwing a ball When throwing a ball
straight up, which of the straight up, which of the
following is true about its following is true about its
velocity velocity vv and its acceleration and its acceleration aa
at the highest point in its path?at the highest point in its path?
a) both a) both v = 0v = 0 and and a = 0a = 0
b) b) v v 0 0, but , but a = 0a = 0
c) c) v = 0v = 0, but , but a a 0 0
d) both d) both v v 00 and and a a 0 0
e) not really suree) not really sure
43
The ball rolls up the ramp, then back down. Which is the correct acceleration graph?
44
The ball rolls up the ramp, then back down. Which is the correct acceleration graph?
Rubber Ball I
v
ta
v
tb
v
tc
v
td
You drop a rubber ball. Right after it leaves your hand and You drop a rubber ball. Right after it leaves your hand and
before it hits the floor, which of the above plots represents before it hits the floor, which of the above plots represents
the the v v vs.vs. t t graph for this motion? (Assume your graph for this motion? (Assume your yy-axis is -axis is
pointing up).pointing up).
Rubber Ball I
v
ta
v
tb
v
tc
v
td
You drop a rubber ball. Right after it leaves your hand You drop a rubber ball. Right after it leaves your hand
and before it hits the floor, which of the above plots and before it hits the floor, which of the above plots
represents the represents the v v vs.vs. t t graph for this motion? (Assume graph for this motion? (Assume
your your yy-axis is pointing up).-axis is pointing up).
v
td
v
tb
v
tc
v
ta
You toss a ball straight up in the air and catch it again. You toss a ball straight up in the air and catch it again.
Right after it leaves your hand and before you catch it, Right after it leaves your hand and before you catch it,
which of the above plots represents the which of the above plots represents the v v vs.vs. t t graph graph
for this motion? (Assume your for this motion? (Assume your yy-axis is pointing up).-axis is pointing up).
Rubber Ball II
v
td
v
tb
v
tc
v
ta
You toss a ball straight up in the air and catch it again. You toss a ball straight up in the air and catch it again.
Right after it leaves your hand and before you catch it, Right after it leaves your hand and before you catch it,
which of the above plots represents the which of the above plots represents the v v vs.vs. t t graph graph
for this motion? (Assume your for this motion? (Assume your yy-axis is pointing up).-axis is pointing up).
Rubber Ball II
v
ta
v
tb
v
tbv
td
You drop a very bouncy rubber ball. It falls, and then it You drop a very bouncy rubber ball. It falls, and then it
hits the floor and bounces right back up to you. Which hits the floor and bounces right back up to you. Which
of the following represents the of the following represents the v v vs.vs. t t graph graph for this for this
motion?motion?
Rubber Ball III
v
ta
v
tb
v
tbv
td
You drop a very bouncy rubber ball. It falls, and then it You drop a very bouncy rubber ball. It falls, and then it
hits the floor and bounces right back up to you. Which hits the floor and bounces right back up to you. Which
of the following represents the of the following represents the v v vs.vs. t t graph graph for this for this
motion?motion?
Rubber Ball III