Transcript Newton`s Laws presentation

May the “Force” be with you!
Newton's Laws &
NASA’s GLAST/Fermi Space Telescope
Teena Della
Astrophysical Ambassador, NASA, Sonoma State University E/PO
Water Slide video
Play time:
• For the next 25 minutes play through as
many of the hands-on stations as
possible.
• Fill out your reflection sheets at each
station. Be sure to PREDICT first.
• BE the student.
• Work together and have fun.
• Later we will reflect as a group.
Figure Skater
To begin moving,
a figure skater must apply a force using her skates.
Once in motion,
she’ll continue to glide along the ice in a straight line for a long time
unless she applies another force.
Snowboarder
A snowboarder experiences a
force due to gravity which
pulls her down.
She will move
in a straight line
unless she applies
a force to the board,
changing her direction.
Train
A train is a very massive object,
and therefore has a lot of inertia.
Once in motion, it is very difficult to stop,
requiring a very large force to slow it.
Car Hitting a Wall
A car rolling down a hill is being moved by the force of gravity.
When the car hits the wall, the greater inertia of the wall stops it.
But anything not attached to the car will still move forward,
So the man running after the car
will lose his coffee, his lunch, and his briefcase.
GLAST/Fermi &
Newton’s 1st Law of Motion
• On June 11, 2008, the GLAST
satellite was sealed in the nosecone of a Delta 2 rocket, ready
for launch from Cape Canaveral,
Florida. Immediately prior to
launch, GLAST was ‘an object at
rest’, and so was the rocket.
There was no unbalanced force
on GLAST or the rocket, so both
remained at rest.
GLAST Launch
June 11, 2008
GLAST/Fermi &
Newton’s 1st Law of Motion
• When were GLAST and the
rocket at rest?
• When were GLAST and the
rocket in motion in a straight
line?
Tug of War
When each end of a rope is pulled,
the rope will move in the direction of whomever is pulling harder,
whomever is applying more force.
In this case, the magnitude or strength of A (on the right)
is greater than that of B (on the left),
so the rope accelerates to the right.
Waterfall
As the water flows over the
edge of the rocks,
gravity, which exerts a
downward force on it,
causes it to accelerate
downward.
The water moves faster the
longer it falls.
Trucker and Ramp
When the man pushes the heavy
box up the ramp, he applies a
force to the box.
The box reacts by pushing back.
If the man pushes hard enough,
he can overcome
gravity and friction,
accelerating the box up the ramp.
Throwing a Ball
When the girl throws the ball, she is applying a
force to it and accelerating it.
As soon as she lets go, gravity,
which also applies a force,
accelerates the ball downward.
Cube being Pulled
A heavy cube
sits on a surface.
If someone
applies a force to it
that is stronger
than the effect of gravity
and the frictional forces on it,
then the object will accelerate.
Swinging
When a girl swings, gravity
accelerates her downward from
the top of her arc.
Her inertia keeps her moving at the
bottom, and the force of the
tension in the ropes makes her
move in an arc upwards.
Gravity then pulls her down,
decelerating her until she stops,
and the motion repeats.
Swivel Chairs
The velocity of an object includes
its speed and its direction.
Acceleration is the change in
velocity,
so changing the speed and/or the
direction of an object is an
acceleration.
In a swivel chair, the woman feels
an acceleration because her
direction is constantly changing
as she spins.
Baseball Player
A baseball player applies a
large force to a baseball,
accelerating it to high
velocity.
If the ball had more mass,
that same force would
not accelerate the ball to
such a high velocity.
Cars
When a driver hits the gas, the wheels apply a force on the ground
due to friction. This force accelerates the car forward.
The brakes apply a force to the wheels, which in turn apply a frictional
force to the ground, decelerating the car.
So the gas pedal and the brakes are both accelerators, since they
change the speed of the car.
Because velocity is the combination of speed and direction, the
steering wheel is an accelerator too! It changes the direction, and
therefore the velocity of the car.
GLAST/Fermi &
Newton’s 2nd Law of Motion
• GLAST has a mass of 2557 kg,
about the total mass of 36
people. To get GLAST into orbit,
it was launched from a Boeing
Delta rocket which is about
232,000 kg.
• When the rocket fires, an
unbalanced force acts on the
rocket, this changes the velocity
by changing its speed &
direction – acceleration.
• An unbalanced force on an
object produces acceleration.
Jogger
A jogger experiences many forces
while running:
• Gravity
• The push of her feet,
• Friction of her shoes on the
ground,
• Air resistance.
The ground pushes back with an
equal and opposite force
propelling her forward.
Rocket
A rocket works by propelling mass
out the back end at high velocity.
The action of the mass of the
burning fuel accelerating out the
back end applies an opposite
reaction force to the rocket,
moving it forward.
The rocket is not simply pushing
against the ground.
This works even in the vacuum of
space.
Shopper
The woman
pushing a
shopping cart
feels an
opposite force
applied by the
cart on her.
Baseball Player
When the baseball player
hits the ball with her bat,
the ball reacts by pushing
back on her.
The player feels this as a
jerk backwards when the
bat contacts the ball.
Fish
Fish propel themselves forward
by pushing water back with their tails.
The water reacts by pushing the fish in the opposite
direction, forward.
Hand Pulling On Rope
Connected to a Weight
When the hand pulls the rope attached to the weight,
it applies a force to the weight.
The weight reacts
by applying a force in the opposite direction.
The hand feels a resistance.
Bridge
Suspension bridges are all about actions and reactions.
The main cables push the support poles down,
and the poles react by pushing back with an equal but opposite force.
Cables hanging down from the main cables pull the main cables down, which
react by pulling back on the vertical cables.
The roadway hangs from the vertical cables, pulling them down, and the
vertical cables react by holding the roadway up.
Soccer Player
When the boy runs up to the ball and kicks it, he applies a force
to the ball, moving it forward.
The ball reacts by pushing back against the boy, which he feels
as pressure on his foot when he kicks the ball.
Hammer and Nail
The hammer hitting the nail
applies a large force to it.
The nail reacts
by pushing back
against the hammer.
The carpenter feels this
as a jolt backwards
against his hand.
GLAST/Fermi &
Newton’s 3rd Law of Motion
• At launch, the exhaust
exits from the base to
propel it upwards through
the atmosphere.
• There is an equal and
opposite force directed on
the rocket – the rocket
pushes the exhaust
stream down with the
same force as the exhaust
stream pushes the rocket
upwards.
The parts of GLAST
Large Area
Telescope (LAT)
GLAST Burst
Monitor (GBM)
GLAST/Fermi &
Newton’s 3rd Law of Motion
• GLAST will slew so that the telescopes
on board turn and point at the gamma ray
bursts (GRB.)
• To begin to slew the satellite spins the
attached flywheels to point at the GRB.
• This turns GLAST in the opposite
direction, another example of Newton’s
3rd Law of Motion.
Song Time
• “Laying Down the Laws of Motion”
• A cute song about Newton’s 3 Laws of
Motion
• An alternative/fun way to present topics –
students love music and remember lyrics
• http://www.songramp.com/mod/mps/viewtrack.php?trackid=66355
Play Song
lyrics next page
The physicist will not insist you learn the wizard's potion
But minds will grow if students know of Newton's Laws of Motion
Isaac Newton studied forces; forces make things start and stop
Students taking science courses learn these laws to stay on top
Things in motion stay in motion; things at rest will stay at rest.
Inertia's our initial notion; know it and you'll pass the test.
We're laying down the law; we're laying down the law;
We're laying down the laws of motion.
The next law's also worth a mention so wisdom will accelerate.
Although I sense your apprehension, a speedy lesson is your fate.
page 1 of 2
With your elbow, wrist and shoulder, here is how you must
proceed
Throw a ball and throw a boulder, greater mass means lesser
speed.
We're laying down the law; we're laying down the law;
We're laying down the laws of motion.
One last law we'll be explaining, says forces always come in pairs.
Newton's law will leaving you straining when you're climbing up
the stairs.
Each step you take is called an action; push a wall, it pushes back
When you act, expect reaction; equal and opposite, that's a fact.
We're laying down the law; we're laying down the law;
We're laying down the laws of motion.
Solar System
All the planets in the solar system
orbit the Sun due to its gravity.
The inner planets are closer to the Sun
and feel more gravity,
so as a result they move faster.
Astronaut
Gravity goes on forever;
an astronaut in orbit
is accelerated
by Earth’s gravity.
Without
the balancing upward force
from the ground,
he falls freely.
Some people call this “weightlessness,”
but that’s not really true.
“Free fall” is a better term.
Sir Isaac Newton
Isaac Newton realised
that all massive objects
in the Universe
apply the force of gravity
to all other massive objects.
An apple didn’t really fall
on his head,
but he did realise that
the force causing an apple to fall
is the same as
the force causing
the Moon to orbit the Earth –
The Earth’s gravity.
Cyclist
Bicyclists climbing a hill –
or speeding down one –
are certainly
aware of gravity!
GLAST Satellite
• Why does GLAST not fall to
the Earth?
• GLAST moves horizontally
in its orbit at just the right
rate so that as it falls toward
Earth, its horizontal motion
creates a circular path
around the Earth.
• This balance between
‘horizontal’ and ‘vertical’
motion is what is meant by
being ‘in orbit’.
For more information visit. . . .
• http://www.nasa.gov/mission_pages/GLAST/news/
• http://epo.sonoma.edu/
• Email: [email protected]
• http://public.sd43.bc.ca/secondary/terryfox/tdella