Motion Observing To observe an object in motion, you must use a referenced object. The one sitting...

Motion

Observing

To observe an object in motion, you must usea referenced object. The one sitting still is consideredto be the reference point.

When an object changes position over time, comparedto the reference point, the object is said to be in motion

When an object is at rest, what is its speed?

2 mph

1 mph

3 mph

0 mph

0%

87%

7%7%

1. 2 mph

2. 1 mph

3. 3 mph

4. 0 mph

Motion is change in ____.

speed

velocit

y

eyelin

er

position

56%

11%6%

28%

1. speed

2. velocity

3. eyeliner

4. position

A reference point for determining position and motion could be

Cloud

Building

A movin

g objec..

.

All of t

he abo...

0%

28%

61%

11%

1. Cloud

2. Building

3. A moving object

4. All of the above

Chemistry

Inertia is a function of mass.

Inertia - tendency of an object to resist changes in its direction

In other words an object stays at rest untilsomething causes it to move

Small objects have small inertiaMassive objects have large inertia

Inertia

A person in a head-on car collision who is not wearing a seat belt continues to move forward at

the original speed of the car because of ____.

Inerti

a

Balance

d force

Grav

ity

Dru

nk driv

er

44%

0%

39%

17%

1. Inertia

2. Balanced force

3. Gravity

4. Drunk driver

Which one of the following objects has the greatest inertia?

pencil

Bowling b

all

Baseball

Your head

6% 6%11%

78%1. pencil

2. Bowling ball

3. Baseball

4. Your head

Motion

Speedthe rate at which an object moves

two variables need to be considereda. distanceb. time

therefore:

speed = distance time (s)

The distance traveled divided by the time it took to travel that distance determines an

object's

Acceleration

Position

Speed

Force

35%

0%

59%

6%

1. Acceleration

2. Position

3. Speed

4. Force

The SI unit for speed is

Km/foot

feet/s

econd

meter/s

econd

mile

/hour

0%

62%

23%15%

1. Km/foot

2. feet/second

3. meter/second

4. mile/hour

Motion

Average speed is a measure of the distance traveled in a given period of time; it is sometimes referred to as the distance per time ratio. Suppose that during your trip to school, you traveled a distance of 5 miles and the trip lasted 0.2 hours (12 minutes). The average speed of your car could be determined as

MotionVelocitythe speed of an object in a particular directionFor example: 15 m/s east

or 22 m/s southwest

velocity always includes which way; N, S, E or W

Velocity is determined by speed and direction

True

False

25%

75%1. True

2. False

Motion

Resultant velocitythis calculation is determined as follows

How fast is the boy moving?a. if velocity is in the same direction

e.g.

b. if velocity is in opposite directionse.g.

If a bus is traveling south at 15 mph and a boy stands and walks north at 1 mph what is

the resultant velocity

15 mph

1 mph

14 mph

16 mph

0% 0%

100%

0%

1. 15 mph

2. 1 mph

3. 14 mph

4. 16 mph

If a bus is traveling south at 15 mph and a boy stands and walks south at 1 mph what

is the resultant velocity

15 mph

1 mph

14 mph

16 mph

6%

56%

33%

6%

1. 15 mph

2. 1 mph

3. 14 mph

4. 16 mph

Motion

Accelerationis the rate at which velocity changes

to apply a force to an object to make it either slow-down,speed-up or change direction.

To calculate acceleration:

Acceleration = final velocity– starting velocity time it takes to change velocity (s)

= mps s

Motion

What is the acceleration of a dragster that goes from 0 to 300 mps in 5 seconds?

100 mph/s

600 mph/s

60 mps/s

50 mph/s

6%

28%

56%

11%

1. 100 mph/s

2. 600 mph/s

3. 60 mps/s

4. 50 mph/s

The acceleration of an object

1. Does n

ot de...

2. is al

ways o...

3. is al

ways i...

4. None of t

he...

6%

44%

28%22%

1. Does not deal with force

2. is always opposite of the force that was applied.

3. is always in the same direction as the force.

4. None of the above

Acceleration of an object

Slows d

own wit.

..

Incre

ases w

ith...

Is in

the sa

me...

All of t

he abo...

18%

53%

6%

24%

1. Slows down with increase in weight

2. Increases with force

3. Is in the same direction

4. All of the above

Observe the animation of the three cars below. Which car or cars (red, green, and/or blue) are undergoing an acceleration? Study each car individually in order to determine the answer.

Now that you've answered the first question correctly, try this one: which car (red, green, or blue) experiences the greatest acceleration?

As a final test of your understanding, consider the position-time graph at the right. Each one of the three lines on the position-time graph corresponds to the motion of one of the three cars. Match the appropriate line to the particular color of car.

Motion

either a push or a pull

Unbalanced forceproduces a change in acceleration

net force is greater than zero

Balanced forceproduces no acceleration

net force is zero

Force

Motion

Net force is the combination of 2 forces

A force is which one of these?

Push Pull

Push or P

ull

None of t

he ab...

6% 0%

94%

0%

1. Push

2. Pull

3. Push or Pull

4. None of the above

When two birds are pulling on a worm and the worm moves toward the first bird, you

know that the forces are ____.

Balance

d

Unbalance

d

Action-re

actio...

Unfair

0% 0%6%

94%1. Balanced

2. Unbalanced

3. Action-reaction

4. Unfair

Which of the following is NOT an example of a force being exerted?

Pushing open a...

Sitti

ng in a c.

..

Texting

None of t

he ab...

0%

65%

18%18%

1. Pushing open a door

2. Sitting in a chair

3. Texting

4. None of the above

Balanced forces applied to an object makes that object

Stay a

t rest

Change directi

on

Accelerate

Slows d

own

65%

24%

6%6%

1. Stay at rest

2. Change direction

3. Accelerate

4. Slows down

You have made a house of cards on top of your table. Suddenly, a gust of wind blows through an open window and your house of cards comes tumbling down. The wind

applied ____ to your house of cards.

Grav

ity

Balance

d

Fricti

on

Centipedal

Unbalance

d

28%

0%

39%

11%

22%

1. Gravity

2. Balanced

3. Friction

4. Centipedal

5. Unbalanced

hills and valleys

Motion

force that opposes motion between twosurfaces that are touching

Greater the force, greater the friction

Friction

The force that opposes motion

Grav

itational

Balance

d

Unbalance

d

Fricti

on

36%

57%

0%7%

1. Gravitational

2. Balanced

3. Unbalanced

4. Friction

One way to increase friction is to use

wax

wate

r sa

nd oil

7%

21%

57%

14%

1. wax

2. water

3. sand

4. oil

MotionGravity and Motion

all objects fall to the ground at the same rate

how? difference in force is canceled by the difference in mass

What would hit first, elephant or feather?

Motion

Air resistance slows down acceleration

air resistance continues to increase until it matchesthe downward force of gravity

object then falls at a constant velocitycalled terminal velocity

Motion

Another example of terminal velocity

Remember, the increase in air resistance continuestill it is even with gravity

Motion

Free fallno air resistance

can only occur in a vacuum

the only force acting is gravity

Motion

Three laws that relate force to the motion of objects

First law aka. law of inertiaAn object at rest tends to stay at rest and an

object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force.  

Newton’s Laws of Motion

Examples of Newton’s 1st Law

Newton’s first law of motion applies

Moving objects

No m

oving obje...

Speed

Both 1 and 3

0% 0%0%0%

1. Moving objects

2. No moving objects

3. Speed

4. Both 1 and 3

CountdownCountdown

10

According to Newton’s first law of motion, a moving object that is not acted on by an

unbalanced force will

Remain in m

oti... St

op

Blow up

Accelerate

0% 0%0%0%

1. Remain in motion

2. Stop

3. Blow up

4. Accelerate

CountdownCountdown

10

Newton’s first law of motion states that an object stays at rest unless a(n) ____ acts on

it.

Balance

d force

Grav

itational ..

.

Unbalance

d for..

.

Fricti

on force

0% 0%0%0%

1. Balanced force

2. Gravitational force

3. Unbalanced force

4. Friction force

CountdownCountdown

10

Motion

Second Law due to unbalanced forcethat the acceleration of an object is dependent

upon two variables a. the net force acting upon the object and b. the mass of the object

Examples of Newton’s 2nd Law

MotionThird Law

that for every action (force) in nature, there is an equal and opposite reaction; force pairs

in other words: if object A exerts a force on object B, then object B also exerts an equal force on object A

note: we are only talking about forces

Examples of Newton’s 3rd Law

Motion

Momentumproperty of a moving object that dependson the object’s mass and velocity

in other words: more momentum an object has theharder it is to stop the object

Conservation (constant) of momentumThat is, the momentum lost by object 1 is equal to the momentum gained by object 2

MotionEnergy

the ability to do work

remember, work is a transfer of energy so thereforework only occurs if the force and motion are in the same direction

Work = F x d; force times distance

since force is in Newtons (N) and distanceis in meters the new label is J or Joules

Motion

Energy of Motioncalled kinetic energy

as long as an object is moving there is kinetic energy

kinetic energy depends on mass and velocity

creating work

MotionEnergy of position

called potential energy

gravitational potential energy depends on weight and height

tells us about stored energy that has thecapacity to do work

Motion

Mechanical energykinetic energy + potential energy

as the height decreases the PE also decreases

as the speed increases so does the kinetic energy

MotionTypes of energy

MotionConservation of energy

energy can be neither created nor destroyedtotal amount of energy in a closed system is always the same

with conversion of energy you always get thermal energy

what are the energies in the rollercoaster ride?

Motion

Temperature temperature depends on the kinetic energyof the particles

as a substance gets hotter, it’s particles moves faster

Motion

Temperature conversion

Motion

Heattransfer of energy between objects of different temperatures

energy is transferred from higher temperatures tolower temperatures

Motion

Types of energy transfer

a. conduction – heat transfer by direct contacthigher kinetic energy to lowerkinetic energy

b. convection – heat transfer by movementof liquid or gas

c. radiation – heat transfer as electromagnetic waves