Transcript Text P409-413 Mass and Inertia The universe consists of matter in motion The greater the mass the harder it is to move. And .

Text P409-413
Mass and Inertia
The universe
consists of matter
in motion
The greater the mass
the harder it is to move.
And . . .
the harder it is to stop moving.
Lower mass objects are easier to move . . .and to
stop moving.
NEWTON’s Laws
1st Law of Motion :
An object remains at a
constant speed
in a straight path ,until a net
force acts on it.
NEWTON’s 1st Law of Motion
is the law of
An object will
remain at a
constant speed
(unless disturbed).
Momentum = mass x velocity
Higher mass higher momentum
Higher velocity higher momentum
includes velocity.
So, it has direction.
Momentum points in the
direction of motion.
Conservation of momentum
When objects collide, all of the
momentum goes somewhere.
Conservation of momentum
When objects collide, all of the
momentum goes somewhere.
Conservation of momentum
When objects collide, all of the
momentum goes somewhere.
Conservation of momentum
When objects collide, all of the
momentum goes somewhere.
NEWTON’s
nd
2 Law of Motion :
An object that
has a force
acting on it will
change its speed
(accelerate).
Net force is the total amount of Force (minus
the forces that cancel each other out).
Force of gravity
Force of muscles
Net force
When the net force is Zero.
-> NO movement
When the net force is NOT Zero.
-> movement
Static Equilibrium Balanced forces
When all forces are balanced.
The net force is Zero.
There is NO movement.
3 Kg
?
2 Kg
50 N
50 N
50 N
50 N
NEWTON’s
3rd Law of Motion:
For every action there is
an equal and opposite reaction.
NEWTON’s
3rd Law of Motion:
For every action, there is
an equal and opposite reaction.
NEWTON’s
3rd Law of Motion:
For every action, there is
an equal and opposite reaction.
Gravity
Action
Inertia
Friction
Balanced or unbalanced?
Reaction
A car is traveling down a hill. Which
of the following will affect the amount
of energy the car has?
how long the car is
the time of day
how much the car weighs
the color of the car
Friction
the resistive force that occurs
when two surfaces travel past
each other.
causes physical deformation
generates heat
Friction
the resistive
force that
occurs when
two surfaces
contact each
other.
Oliver the dog doesn't want to
walk in the rain. He can make his
owner pull harder on the leash to
get him out the door by
sitting on the vinyl floor.
sitting on the tile floor.
sitting on the carpeted floor.
sitting on the wood floor.
terminal velocity gravity will
accelerate an object until air
resistance (friction) does not
allow it to go any faster.
In the absence of air resistance,
which of these objects will fall at
the fastest rate when dropped?
the ball with a mass of 75 kg
the ball with a mass of 25 kg
the ball with a mass of 10 kg
They all fall at the same rate.
Gravitational force
Gravitational force
Gravitational force
o INCREASES with Mass
o DECREASES with Distance
All objects in the universe are
attracted to each other by the
force of
effort.
friction.
gravity.
inertia.
THE END
• Do Q 1-7, P413
Four pairs of objects have the masses
shown below. If the objects in each pair
are the same distance apart, the
gravitational force between the objects
in which pair is greatest?
1 kilogram and 1 kilogram
1 kilogram and 2 kilograms
2 kilograms and 1 kilogram
2 kilograms and 2 kilograms
Simple Machines and work
Lever
Inclined plane
Pulley
Wedge
Screw
Wheel and axle
Simple
Machines
• Pulley
• Wheel &
Axle
• Lever
• Inclined plane
• Screw
• Wedge
• Gear
Simple Machines
Pulley
Inclined plane
Wheel & Axle
Screw
Lever
Wedge
Gear
Which activity involves the use of
a simple machine?
riding on a seesaw
flying a kite
listening to a radio
skiing down a hill
Simple Machine
A mechanism that lowers
the amount of force needed
to do work, by increasing
the distance.
On which simple machine is a
fulcrum found?
pulley
wheel
axle
lever
Which of the following is often
used as a lever?
file
nail
saw
crowbar
The Wedge
The bottom of this light bulb is
an example of what type of
simple machine?
a lever
a pulley
a screw
a wedge
What type of simple machine is
used to split things apart?
screw
wheel and axle
wedge
inclined plane
What type of simple machine is
used to pull a flag up to the top
of a flagpole?
screw
wheel and axle
inclined plane
pulley
Centripetal force
The inward force
on a spinning object,
that stops it
from going in
a straight line.
Perpendicular
Centripetal force
Centripetal force
The inward
force
on a
Spinning
object.
Centripetal force
The
inward force
on a
Spinning
object.
Satellites stay in place as they orbit
because of . . .
the repeated firing of rocket
boosters.
the gravitational pull of Earth.
a narrow path through the vacuum
of space.
solar panels generating energy to
hold them in place