Transcript Motion

Slow projectile - shoot a
monkey
Fast projectile - shoot a
monkey

You will be able to explain:
› Motion
› Distance
› Speed
› Velocity

Motion- when an objects distance from
another object is changing
› Reference point- place used as a
comparison to determine motion

Distance- always measured using the
metric system

Kilometers, meters, centimeters,
millimeters

Speed- the distance an object travels
per unit time
 Speed=Distance/Time

Speed=
M/Second

1 meter per second = 2.23693629 miles
per hour
Student
Number
Distance
1
2
3
4
.
.
10 m
10 m
10 m
10 m
.
.
Time
Speed
m/s
Speed mph
Avg.
Avg.
 The
pitchers mound is 60’ 6” from
home plate. This is equal to 18.39 M.
 If it takes a pitch 1 second to get to
home plate, how fast was the pitch?
 Remember 1 meter per second =
2.23693629 miles per hour
 Answer=

Speedsters

Ndamukong Suh
Velocity is speed in a direction.
 V=D/T


Velocity is a vector quantity that refers to "the rate at
which an object changes its position." Imagine a person
moving rapidly - one step forward and one step back always returning to the original starting position. While this
might result in a frenzy of activity, it would result in a zero
velocity. Because the person always returns to the original
position, the motion would never result in a change in
position. Since velocity is defined as the rate at which the
position changes, this motion results in zero velocity. If a
person in motion wishes to maximize their velocity, then
that person must make every effort to maximize the
amount that they are displaced from their original
position. Every step must go into moving that person
further from where he or she started. For certain, the
person should never change directions and begin to
return to the starting position.
1.
2.
3.
Ben Roethlisberger can throw a football 60
yards in 4 seconds. How many ft/ second is
that?
If there are 5,280 ft per mile, how fast is Big
Bens pass in mph?
A bullet from a sniper rifle can travel 5,760 ft/
second. How many miles/ hr is that? How far
would it travel in 10 seconds?
If a train travels 275 miles in in 5 hours, what is
its average speed? What is its velocity?
If I throw a boomerang out at a40 mph and
it returns at a speed of 40 mph, what is its
average speed? What was its velocity?
3927mph
4.
5.
A=(End
V - Start V)/time

Newtons Second Law- Force

Force- the product of an objects
acceleration and mass Measured in
Newtons
 Force = Mass x Acceleration

You can rearrange the formula to find
acceleration or mass if needed
 Acceleration = Force/Mass

Force in sports video
A 52 kg water skier is being pulled by a
speedboat. The force causes them to
accelerate at 2 m/s. Calculate the net
force that causes this acceleration.
 What is the net force of a 1000 kg
elevator accelerating at 2 m/s?
 What net force is needed to accelerate
a 55 kg cart at 15 m/s?

How can I increase the force of a
football players tackle?
 How can I increase the force of a
paintball to increase its range?


Friction- the force that two substances
exert as they rub past each other

Lets burn something old school style!!!
Stick fire

There are three types of friction
› Sliding friction-when solid surfaces slide over
one another
› Rolling friction-when an object rolls over
another object
› Fluid friction-when an object moves through
a liquid or gas
Phonebook Friction
 Meter Stick friction demo

› Take a meter stick and slide your hands
towards oneanother and notice where they
meet.
› Now start one 50% closer to the middle of
the stick and notice where they meet.
› Why?

Do you think that a quarter, dime, or
nickel will fall more quickly?
› Place a quarter, dime, and nickel at the
edge of your desk.
› Put a ruler behind them so they can be
pushed off evenly.
› Push all three over the edge at the same
time.

What was the result?

List an example of the three types of
friction.

How does friction affect force?

What is often a byproduct of friction?
Gravity- the force of two objects pulling
towards each other
 9.8 m/s2
 So each second an object falls its
velocity increases by this rate until
terminal velocity is reached.
 Air resistance has an effect on gravity
 Killer Penny

Bullet Drop vs. Shot
 Notice the math these guys do. Proof
that math is cool.


Lets look at the book pg. 58
An object can only fall so fast. At some
point it reaches what is known as
TERMINAL VELOCITY
When air resistance = Gravity
For a human this is at about 53m/ S or
120mph
2

Calculate your velocity if you jumped
from an airplane and fell for 11 seconds.
Gravity= 9.8 m/S2
Calculate your velocity if you jump from
a swing at 10 ft.
Conversion-

Objectives
› Use Proper Scale
› Determine X & Y axis labels
› Determine speed, acceleration, and velocity
by using graphs

If an object exerts force on another
object, the second object exerts the
same force in the opposite direction.

So what does that mean?
› It means if you and a friend stand on an icy
surface and one of you pushes the other
you both move equal distances

Momentum- is the quantity of motion
› Momentum = Mass X Velocity

Which has more momentum:
› A 3 kg sledgehammer swung at 1.5 m/s or a
4 kg sledgehammer swung at .9 m/s?
› A 90 kg hockey player skating at 10 ft/s or a
75 kg player skating at 17 ft/s
› A 142 gram baseball going 95 mph or a 190
gram softball traveling 74 mph?
Pressure Pascal Fluid Pascal’s Principle Hydraulic system Buoyant force Archimedes Principle Density Bernoulli’s principle

You and your team will have one week to
build a glider from Styrofoam. The goal will
be the longest flight from my rescue
window. You will receive one full class
period the day before the flight and 10 min.
of each class period up until the flight. The
tools for this assignment will be :




Foam
Glue
Paper clips
Bernoulli’s Principle

Pressure = Force/Area
› Measured in Pascal's (Pa) 1N/M2 =1Pa
Or
N/cm2 for smaller units

Book pg. 78

The air around us exerts pressure on our
body.
› Why don't we get crushed?
Air pressure at sea level =10.13N/cm2
 More often we use a more common
measure of air pressure (mmHg)

› 1 mm Hg = 133.322368 Pascal's
› 760 mm Hg is the standard air pressure at sea
level. This is known as Barometric pressure

Air pressure is less at elevation. So, water
boils espier because the molecules are
freed more easily.
› What affect does this have on cooking
times?
› Soda Can
› 55 Gallon Drum
As you go deeper the pressure increases.
 Pg. 83
 Water Bottle


Buoyant force- force that works against
gravity to keep things afloat
Sinking- when gravity has more force
than buoyancy
 Floating when buoyancy equals or is
greater than gravity
 Archimedes Principle- the buoyant force
of an object is equal to the weight of
water that object displaces


Density= mass/volume

Density determines weather or not
something will float

If I have a block that is ten cm long by 20
cm wide by 30 cm deep, and its mass is
1000 g, what is its density?

What is the density of a liquid that fills a
100 ml beaker and weighs 100 grams?
What liquid would this most likely be?

If a wooden block has a density of 2
g/cm3 will it float or sink?

The faster a fluid moves the less pressure
it exerts.

This is why a plain can fly.