2. Sir Isaac Newton
• Sir Isaac Newton is credited
for discovering Gravity:
One day Newton was sitting
in an orchard under an
apple tree and noticed
apples falling to the ground.
Maybe an apple hit him on
the head and maybe it
didn’t. Like all good
scientists, Newton collected
and examined the data (the
apple) and ate it.
3. Law of Gravity
• All particles of matter are
attracted to all other particles of
matter with an attraction that is
directly proportional to the
masses of the objects and
inversely proportional to the
distance between the objects.
OR
• There is an attraction between
all things.
4. • After developing the Law of Gravity, Newton continued to
work with objects of matter and determined how they
reacted with each other. This work led him to the
development of what is now called:
PHYSICS
Newton’s Three Laws of
Motion
5. Newton’s First Law of Motion
The Law of Inertia
• Objects at rest stay at rest unless acted upon by an
unbalanced force and objects in motion stay in
motion in a straight line and at a constant speed
unless acted upon by an unbalanced force.
7. Newton’s Second Law of Motion
The Law of Acceleration
• Objects acted upon by an unbalanced force
accelerate in the direction of the force directly
proportional to the magnitude of the force and
inversely proportional to the mass of the object.
8. Newton’s Third Law of Motion
The Law of Action and Reaction
• For every action by a
force there is an equal
and opposite reaction by
a different force.
10. G-Force
• The “G” stands for Gravity.
• Currently you are at 1 G
• If you weighed 100 pounds and went to 2 G
you would FEEL like you weighed 200 pounds.
11. Positive G Forces
• Upward acceleration.
• Forces blood away from the brain and toward
the feet.
• A typical person can withstand around 5 g
before G-LOC.
12. Negative G Forces
• Negative g’s are usually experienced during a
steep dive in an aircraft where you would feel
your weight lessening.
• As little as 2-3 g’s would cause your eyes'
blood vessels to start rupturing. This is called a
"red out".
13. Examples
Gs
Bugatti Veyron from 0 to 100 km/h in 2.4 s 1.18
High-g roller coasters 3.5–6.3
Top fuel drag racing world record of 4.4 s over
1/4 mile
4.2
Sprint Missile 100
Rating of electronics built into military artillery
shells
15,500
14. Effects on Body
• A normal healthy person would start
experience loss of vision at around 5-6 g
• Roller coasters give forces of maximum up to
3 to 4 g's for brief periods of time.
• If a force of 4 to 6 g's is held for more than a
few seconds, the results could be
devastating; such as blackouts to death.
• The devastating car crash of Princess Diana
of Wales in 1997 was estimated to range
somewhere between 70–100 g's. This
accident was intense enough to pull the
pulmonary artery from her heart.
15. Links
• Roller Coaster Design
• How Roller Coasters Work
• Roller Coaster Design PBS Kids
18. Simple Machines
• A mechanical device that provides a change in
force that creates a mechanical advantage.
• Changing the direction of a force.
• Few or no moving parts.
22. What is a Lever?What is a Lever?
• A hammer is a lever that helps do work.
• Work is done whenever force makes an object
move.
23. What is an Inclined Plane?
• A ramp is an inclined plane.
• A ramp helps move objects.
• You can use an inclined plane to help move an
object to a higher or lower place.
24. What is a Wedge?
• A doorstop is a wedge.
• A wedge is a simple machine used to push
objects apart.
• An ax is a wedge that splits wood.
25. What is a Screw?
• A screw is a simple machine used to hold
objects together.
• Think about your desk.
• Does it have screws helping to hold it
together?
26. What is a Wheel and Axle?
• A wheel and axle is a simple machine made of
a rod attached to the center of a wheel.
• The axle, or rod, turns when you put force on
the wheel.
• You probably have seen a wheel and axle on
cars, skateboards, etc.
27. What is a Pulley?
• A pulley is a simple machine with a wheel and
with a rope.
• The rope fits around the edge of the wheel.
• You can use a pulley to move a load up, down
or sideways.
29. What is a Catapult?
• In modern times, the word catapult can be
used to describe any machine that hurls a
projectile.
• 3 Types
– Onager
– Ballista
– Trebuchet
30. Onager
• One Arm or Lever
• Torsion Device
– Twisted rope or rubber
bands to create tension.
• Gift from the Romans
31. Ballista
• This machine was deliberately
invented by the Greeks,
around 800 BCE.
• Ballista were even mounted
on warships and used to hurl
fire onto other ships.
• Functions similar to a
crossbow or sling shot.
32. Trebuchet
• The Trebuchet is probably
the oldest type of catapult.
• It was invented either by the
Chinese or in the middle
east.
• Trebuchets were used mainly
as lobbing machines to
spread fire and diseased
corpses, as well as a lot of
solid missiles, over the walls
of castles to rain down on
the inhabitants.
34. Necessary Forces
Speed
Instant Stop (Energy Transfer)
Best ways to increase distance:
1. Apply more force
2. Longer Lever
3. Less Weight in Projectile
4. Angle of Release
38. Force
• Force is the push or pull exerted on an object.
• The magnitude of a force can be found by multiplying
the mass and the acceleration of the object.
• Force equals mass times acceleration.
40. Shape
• “Slippery” – the
object slips
through the air.
• Air should glide
over smoothly as
well as go under.
• Even a mirror or
door handle that
sticks out can
detour
performance.
41. Drag
• The faster an object travels
the more the drag.
• Drag can reduce speed
because it will trace the
overall top of the car.
• Any mistakes or areas that
aren’t smooth will create a
drag force.
• Drag actually pushes in the
opposite direction you want
to go.
42. Lift
• Lift goes underneath
the car and pushed
upward.
• Lift can reduce speed
by actually lifting the
car off the ground.
43. Friction
• Force that opposes
motion.
• This force comes from
the axle rubbing the hole
that was drilled for it.
• To eliminate this take
your pencil and “color”
the axle.
• Friction is often the force
that brings objects to
rest.