Transcript Newton`s Laws of Motion

Newton’s Laws of Motion
Describes motion & changes in
motion.
Newton’s First Law:
An object at rest will remain at
rest; an object in motion will
remain in motion, unless acted
upon by an outside force.
IN OTHER WORDS . . .
AN OBJECT WILL KEEP
DOING WHAT IT HAS BEEN
DOING.
EXAMPLE:
A BOOK SITTING ON A
TABLE WILL REMAIN
THERE FOREVER.
EXAMPLE:
A SKATEBOARD ROLLING
DOWN A SIDEWALK WILL
CONTINUE TO ROLL FOREVER.
Newton’s First Law
EXAMPLE:
A jet on an aircraft carrier; as
gasses come out of the engine, the jet
pushes off in the opposite direction,
with an equal amount of force.
Newton’s Second Law:
The net force on an object is
equal to the product of it’s
acceleration and its mass.
 Force = Mass • Acceleration
EXAMPLE:
THE LARGER THE MASS,
THE GREATER THE FORCE.
or
THE FASTER THE SPEED,
THE GREATER THE FORCE.
EXAMPLE:
IMAGINE YOU’RE RUNNING
TOWARDS THE GOAL LINE WITH THE
FOOTBALL AND YOU’RE ABOUT TO BE
TACKLED. WOULD YOU RATHER BE
TACKLED BY A 125 LB. LINEBACKER OR A
350 LB. LINEMAN? WHY?
EXAMPLE:
WHILE PLAYING BASEBALL,
WOULD YOU RATHER BE HIT WITH A
PITCH TRAVELING 75 MPH OR WITH A
PITCH TRAVELING 100 MPH? WHY?
Newton’s Third Law:
For every action, there is an
equal and opposite reaction.
EXAMPLE:
A runner pushes off the starting
blocks causing him/her to move in
the opposite direction.
Newton’s Third Law
SCIENCE DOESN’T SUCK!!!
IT MAY PUSH or PULL
BUT IT DOESN’T
SUCK !!!
FORCES
A FORCE IS ANY PUSH OR
PULL.
EXAMPLE:
A VACUUM DOES NOT
SUCK; IT PULLS AIR IN, OR IT
PUSHES AIR OUT.
TYPES OF FORCES
BALANCEDUNBALANCED-
TYPES OF FORCES
BALANCED- a force acting on an
object that doesn’t change the objects
motion.
BALANCED FORCES occur when
forces acting in different directions,
and the net force adds up to zero.
NET FORCE- is the sum, when
all forces are added together.
Net Force of 0 = no motion.
Net Force more than 0 = motion occurs.
EXAMPLE:
YOU’RE DRIVING ALONG IN
YOUR CAR TRAVELING 25 MPH,
SUDDENLY ANOTHER CAR HITS YOU
HEAD-ON TRAVELING 25 MPH.
WHAT IS GOING TO HAPPEN?
TYPES OF FORCES
UNBALANCED- a force acting on an
object that changes the objects motion.
UNBALANCED FORCES - is when 2
forces act in opposite directions they
combine by subtraction. If one force
Is greater, the overall force is in the
The direction of the greater force.
EXAMPLE:
YOU’RE DRIVING ALONG IN
YOUR CAR TRAVELING 25 MPH,
SUDDENLY ANOTHER CAR HITS YOU
FROM THE REAR TRAVELING AT 50
MPH. WHAT IS GOING TO HAPPEN?
EXAMPLE:
YOU’RE DRIVING ALONG IN
YOUR CAR TRAVELING 25 MPH,
SUDDENLY ANOTHER CAR HITS YOU
HEAD-ON TRAVELING 50 MPH.
WHAT IS GOING TO HAPPEN?
ELASTIC FORCES
TENSION -
COMPRESSION -
PHYSICS VOCABULARY
Energy - ability to do work.
Force - any push or pull.
Work - force times distance (W= f • d).
Potential energy - stored energy which
is readily available.
Kinetic energy - energy an object has
due to it’s motion.
Newton (N) - unit of force in the metric
system. (Kg • m/s2)
Mass- number of particles an object contains.
Friction- the force between two objects as
they rub together.
Motion- when one object’s distance from
another is changing.
Distance- rate (speed) times time.
Inertia- the tendency of an object to keep
doing whatever it’s doing. The inertia
of an object is measured by its mass.
Speed- how fast something is going; distance
divided by time.
Average speed- the total distance traveled
divided by time.
Velocity- the speed and direction something
is moving.
Acceleration- any change in motion of an
object. Speed or direction.
Net force- the sum total of all the forces
acting on an object.
Average Speed= Final Speed - Initial Speed
2
FORCES WHICH AFFECT MOTION
FRICTION- sliding, rolling, fluid.
GRAVITYAIR RESISTANCE-
Gravity & Terminal Velocity
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WORK
Work = Force • Distance
(W = f • d)
Bernoulli’s Principle