Transcript MOTION

WORD SPLASH
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Motion
speed
distance
graph
car
 Isaac
Newton
 Force
 Frame of
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 Write a story using the
reference
words on the list
velocity
 Underline each word
used
constant
acceleration  Circle words you’ve
never heard in RED
time
 Circle words you’re
familiar with but unsure
of in YELLOW
 Circle words you know
well in GREEN
MOTION
 frame of reference -
comparing an object’s
motion to another object
 Your house stays still as the
cars drive past
 a frame of reference is
necessary in order to describe
motion
 motion change in your position
compared to a frame of
reference.

as a train moves past a platform, people on
the platform see those on the train speeding
by. when people on the train look at one
another, they don't seem to be moving at all
OR moving backwards
 Distance the length of a
path between two points.
 GO METRIC: km, m, mm, cm,
etc.
 Speed distance traveled per
unit of time
 S = d/t
 A car travels 70 km per hour
 Choose units that make sense:
m/s, km/h
 Average speed- the total
distance traveled, d, divided
by the total time, t, it takes to
travel that distance.
speed= distance/time
 Ex- on vacation: 60 km in 0.8 hr, and
35 km in 0.5 hr. What is your
average speed?
 Instantaneous speed the
rate at which an object is
moving at a given moment in
time
 Speedometer in a car
**Average speed is computed
for the entire duration of a trip,
and instantaneous speed is
measured at a particular
instant.
Graphing Motion
 The slope of a line on a
distance-time graph is
speed.
Velocity
 Velocity- the speed and
direction in which an object
is moving
 Velocity is a vector.
 Velocity is CALCULATED the
same way as speed…
 V = d/t
Acceleration
 Acceleration-The rate of
change in velocity
 Changes in speed, direction or
both
 Can Increase (positive) or decrease
(negative)
 acceleration = zero if moving at the
same speed in the same direction
 Constant acceleration is a
steady change in velocity
over time.
 the velocity of the object
changes by the same
amount each second
 A jet taking off.
Calculating Acceleration
Acceleration = Change in velocity = (vf-vi)
time
t
Vf = final velocity
Vi = initial (starting) velocity
Units for acceleration: m/s2 or km/hr2
Graphing Acceleration
 The slope of a speed-time
graph is acceleration
Can be linear or
non linear graph
Force
 force is a push or a pull that
acts on an object.
 can cause a resting object
to move
 can accelerate a moving
object
Acceleration =changes in
____ and/or ____
 Newtons(N)- unit for force
 One N is the force that
causes a 1 kg object to
accelerate at a rate of
1 meter per second every
second (1 m/s2).
 1 N = 1 kgm/s2
 You are carrying a bowl of soup on your
cafeteria tray. As you walk towards your
table, someone suddenly steps out in front of
you. You stop quickly.
 Describe the motion of the soup in the bowl after
you stop.
 Explain why you think the soup behaves like it did.
FORCE
 NET FORCE – Combination of
forces in the same direction or
opposite directions
 Ex. If two people are pushing a
cart at the same time…
FORCE
 Balanced force- when forces
are balanced, net force = 0. No
change in motion (arm
wrestle)
 Unbalanced force- causes a
change in motion
Starter 2/2
Hold a sheet of paper up and let it fall to the
floor.
1. Describe what happens in one line
Hold a crumpled sheet of paper up and let it fall
to the floor
2. Describe what happens in one line.
3. How do the motion of the flat and
crumpled sheet compare? What makes this
happen? (Answer in 2 lines).
FRICTION
 Friction – force that opposes
the motion of objects by
contact
 Static
 Sliding
 Rolling
 Fluid
GRAVITY
 Gravity – force that attracts or
pulls objects together
 Acts downwards toward
center of Earth
 Causes objects to accelerate
as they fall
1. Explain the following in 1 to 2 lines:
Ms. Bell gets upset and pushes Mr. Hill. She also
pushes Ms. Hawbaker with the same force.
Ms. Hawbaker goes further from the push.
2. What factors can affect force?
Newton’s Laws
1st - An object at rest remains at
rest OR an object in motion
remains in motion,unless acted
on by an outside force
Newton’s Laws
st
 1 law
is called the Law of
Inertia.
 Inertia- tendency of object to
resist change in motion.
 seat belts, airbags, etc – these
objects protect you from
inertia.
Newton’s Laws
 2nd – the acceleration of an
object depends on the force
acting on the object and the
mass of the object
 F= (m)(a) OR a= f / m
PRACTICE
 F = (m)(a)
 How much force is required to
move a car with a mass of
2
1200 kg at a rate of 3.0 m/s ?
 What is the force on a 80 kg
box accelerating down a ramp
at 2 m/s2?
Newton’s Laws
 Mass – measure of inertia,
amount of matter in an object
 Weight- force of gravity on an
object
 This formula is a substitute for
F= (m)(a)…
 g = 9.8 m/s2 (on earth)
 Units for weight = newtons (N)
Newton’s Laws
rd
3
– for every action or force,
there is an equal and opposite
reaction or force
 Bumper cars
 If the forces both act on the
same object the object will not
move (net force = 0)
MOMENTUM
•Momentum - describes how mass
and velocity are affected by each
other.
• units are kgm/s
•No velocity? no momentum!
•Conservation of momentum-
The loss of momentum in one
object is the gain of momentum
in another