What is motion Motion is when an object changes its position Motion can be represented mathematically through calculations of speed velocity and acceleration Motion is when an object changes its position ID: 684673
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Slide1
Science CBA #2 ReviewSlide2
Force and Motion
What is motion?
Motion
is
when an object changes its
position
.
Motion
can be represented mathematically through calculations of
speed, velocity, and
acceleration
Motion is
when an object changes its position
.Slide3
Velocity
Velocity has
speed
and
direction
.
Velocity
=
distance + direction
timeSlide4
Displacement
Displacement is
the distance and direction between the starting and ending position.
A
car moved 60 km East and 90 km West. What is the distance?
What is the total distance? __________
___
What is the displacement? __________
___Slide5
A bike rider biked 50 km North and 30 km South. What is the displacement?
What
is the total distance? __________
___
What is the displacement? __________
___Slide6
#1 Velocity
Later that day, they decided to work on their fitness and go run the track. They headed 60 meters southwest from their rooms to the track which took them 20 seconds. What is their velocity?
v =
d+direction
tSlide7
#1 Velocity Answer
d = 60 m SW
t = 20 sec
v = ?
v =
60 m SW
20 sec
v = 3 m/sec/SWSlide8
Speed
The distance an object travels in a certain amount of time.
Average
speed – Total distance divided by total time
Constant
speed - Speed that does not change Slide9
What is the formula for calculating speed?
Speed equals distance divided by time.
Speed
= Distance ÷ Time
Create
the triangle Slide10
Speed Problem
A football field is about 100 meters long. If it takes a person 20 seconds to run its length, how fast was the football player running? Slide11
Speed Problem Answer
Speed = Distance ÷ Time
Speed
= 100 m ÷ 20 s
Speed
= 5m/sSlide12
Acceleration
A change in the direction or speed (velocity) of an object over time – which may be:
-
A
change in speed
Starting
Stopping
Speeding up (positive acceleration)
Slowing down (negative acceleration)
-
A
change in direction
Acceleration is caused by unbalanced forcesSlide13
Unit for Acceleration
m/s
s
Unit for Acceleration
km/hr
sSlide14
I
f
a car is moving on a road at 70 km/hr
going due north, and then changes
direction and starts traveling northeast
staying at 70 km/hr, what happens to its
speed and velocity?
A
The speed of the car changes, but the
velocity stays the same.
B The velocity of the car changes, but
the speed stays the same.
C Both the speed and velocity of the car
change.
D Neither the speed nor the velocity of
the car changes.Slide15
A 2000 kg truck and a 500 kg car are
racing. The same amount of force is
applied to each of them. What will
happen?
A
The truck will accelerate twice as
fast.
B
The car will accelerate twice as fast.
C
The truck will accelerate four times as
fast.
D
The car will accelerate four times as
fast.Slide16
Martin gathered a toy car, a ramp, a
stopwatch, a meter stick, and a variety of
weights. What is he likely testing?
A
how the angle of a ramp affects the
speed of the car
B
how friction affects the speed of the
car
C
how equal forces work on the
placement of the car and the ramp
D
how mass affects the speed of the carSlide17
Practice
What is the speed of a train that runs 4200 km in 21 hours?
s=d/tSlide18
Practice
s= 4200/21
s= 200 km/hr Slide19
Practice
Two people head 60 meters southwest and it took them 20 seconds. What is their velocity
v= distance+ directions
------------------------------------
time
*remember
velocity is speed and directionSlide20
Practice
d= 60 m
sw
t= 20 sec
s=?
v= 60/ 20
v= 30 m/s
swSlide21
Force
The cause of motion (what causes objects to move)
F
orce
has four
components
: push, pull, size, and direction
Force
always
come in
pairs
. It’s impossible to have only
one
forceSlide22
Forces are measured in
Newtons
Symbol: N
•Measured by using a spring scale
•What is a
newton
? A
newton
is a force required to
accelerate
a one kg mass at a rate of one m/s2. Slide23
Net Force
Net Force
:
Net force is the sum of all the forces acting on an object
•
If the forces are in the SAME direction, then you add them together.
5 N --------> 5 N----------->
•
If the forces are in opposite directions then you subtract the smaller force from the larger force.
10 N ------> <---------- 5 NSlide24
Forces may be balanced or unbalanced
Balanced forces
– all forces acting on an object are equal
–There is
NO MOTION
•
Unbalanced forces
– one or more forces acting on an object are stronger than others
–There is
MOTION
•
A NET FORCESlide25
Balanced Forces
Balance force describes
forces
that are
equal
but
opposite
in
direction
; when they act on an object, they
cancel
each other out and
no change
occurs in the object’s
motion
.Slide26
Unbalanced
•Unbalanced forces describe
unequal
forces acting on an object. This results in a
change
in the object’s
motion
in the
direction
of the
larger
force
.Slide27
Newton’s Laws Review
CBASlide28
What is the formal name for Newton’s 1
st
Law?
The Law of Action/Reaction
The Law of Inertia
The Law of Force and Acceleration Slide29
Which law states that “for every action, there is an equal and opposite reaction”?
Newton’s 1
st
Law
Newton’s 2
nd
Law
Newton’s 3
rd
LawSlide30
What is the formal name for Newton’s 2
nd
Law?
The Law of Action/Reaction
The Law of Inertia
The Law of Force and Acceleration Slide31
Which law states, “an object acted on by an unbalanced force will accelerate in the direction of the force”?
Newton’s 1
st
Law
Newton’s 2
nd
Law
Newton’s 3
rd
LawSlide32
What is the formal name for Newton’s 3
rd
Law?
The Law of Action/Reaction
The Law of Inertia
The Law of Force and Acceleration Slide33
Which law states, “an object in motion tends to stay in motion and an object at rest tends to stay at rest until acted upon by an unbalanced force”?
Newton’s 1
st
Law
Newton’s 2
nd
Law
Newton’s 3
rd
LawSlide34
A book is sitting on the table at rest. The forces acting on the book include _______, and these forces are
_______.
Gravity pushing down and the table pushing up; balanced
Gravity pushing down and the table pushing up; unbalanced
Gravity pushing up and friction pushing to the right; balancedSlide35
Tom is teaching Jenny how to ice skate. Both skaters, who are about the same size, are on the ice and wearing their skates. To help Jenny get started, Tom gives her a gentle push from behind
. Which
of the following
best
describes what will happen next
?
Jenny will move backward; Tom will move forward
Jenny will move forward
Jenny will move forward; Tom will move backwardSlide36
What are the four components of force?
Push, Pull, Speed, Direction
Push, Size, Speed, Direction
Push, Pull, Size, DirectionSlide37
Which of the following best describes the difference between speed and acceleration
?
Acceleration is the distance an object travels within a specific unit of time; speed is the measure of the force necessary to change the acceleration of an object
Speed is the distance an object travels within a specific unit of time; acceleration is a measure of the force necessary to change the speed of an object
Speed is the distance an object travels within a specific unit of time; acceleration is the rate at which the speed or direction of an object is changingSlide38
How much force is needed to accelerate a 2,000 kg car at a rate of 8 m/s
2
?
24,000 N
4,000 N
16,000 NSlide39
Reggie accidentally left his books on top of his car before he left for class. The books stayed on top of his car while he was driving north on Oak Avenue. Then, when he made a sharp turn eastward onto Harris Lane, his books fell off the top of his car and onto the street.
Which of the following best explains why Reggie's books fell
?
When Reggie's car turned eastward, his books continued heading northward, causing them to slide off the top of his car and fall
.
The Earth's magnetic field held the books on Reggie's car while he headed north. When he turned east, the magnetic pull faded, causing the books to fall
.
Heat energy from the Sun caused Reggie's books to slide off the top of his car and fall.Slide40
If Sara's father presses on the brakes quickly slowing the car down, what slows Sara down
?
the seat pushing forward on her
her seat belt pulling back on
her
air resistance on the outside of the carSlide41
Jodie sets two objects on a flat surface. Object A has a mass of 50g, while object B has a mass of 250g. Jodie pushes both objects with the same force and watches them accelerate. Which object will accelerate
more?
Object B accelerates more.
Object A accelerates more
.
They accelerate the same amount.Slide42
A car is traveling south at a speed of 65 miles per hour and then begins traveling west but continues traveling at the same speed
. Which
of the following has changed
?
Speed
Mass
VelocitySlide43
Two teams are playing tug-of-war. Each team is pulling on the rope with a force of 500
newtons
. A ribbon is tied to the middle of the rope to determine the winner. Which of the following would result in the greatest acceleration of the ribbon?
A player added to Team B pulls on the rope with a force of 120
newtons
.
A player added to Team A pulls on the rope with a force of 130
newtons
.
A player on Team B who was pulling with a force of 150
newtons
leaves the game.Slide44
Newton's first law of motion states that an object will keep a constant velocity unless acted upon by an unbalanced force.
To test this statement, Martin rolled a ball on a long, level street
. The
ball did not bump into any object, but it eventually came to a stop. How is this possible
?
Every moving object must come to a stop because energy cannot be destroyed
.
Martin did not roll the ball hard enough, which caused the ball to eventually stop rolling
.
The unbalanced force that caused the ball to stop was friction.Slide45
What is the definition of inertia
?
The tendency of a body at rest to stay at rest or of a body in motion to remain in motion
.
The tendency of an object in motion to decelerate
.
The rate at which an object accelerates.Slide46
Plate Tectonics
CBASlide47
The theories of continental drift and sea-floor spreading combined to make the theory of
_______.
plate
tectonics
rejoined
continents
PangaeaSlide48
The Atlantic Ocean is currently growing wider as its floor enlarges due to the process of sea-floor spreading. In sea-floor spreading, pieces of oceanic
crust
move sideways against each other along a transform plate boundary
.
move together along a convergent plate boundary
.
move apart along a divergent plate boundary.Slide49
A tectonic plate applies a downward force onto the
asthenosphere
, which lies beneath the plate. According to Newton's 3rd Law, which can be described as the law of action-reaction
,
the
asthenosphere
applies a force of double magnitude upward onto the tectonic plate
.
the
asthenosphere
applies a force of equal magnitude upward onto the tectonic plate
.
the
asthenosphere
applies a force of equal magnitude downward as well.Slide50
Where the river enters the lake, it branches into many channels and has deposited a large, fan-shaped feature extending out from the shore (marked by "X"). What is this feature?
a sand
dune
a
delta
a barrier islandSlide51
A
subduction
zone is an area where one tectonic plate sinks underneath another one. Volcanoes often form as a result. Which of the following plate collisions would most likely result in a
subduction
zone
?
a piece of continental crust and a piece of oceanic crust meeting at a convergent
boundary
two pieces of oceanic crust meeting at a divergent
boundary
a piece of continental crust and a piece of oceanic crust meeting at a divergent boundarySlide52
Which of the following provides the most evidence for the theory of plate tectonics
?
the spreading of the sea
floor
the locations of the glaciers
the changing of the seasons