Download Newton*s Second Law

101
Newton’s Second Law Notes
Newton’s Second Law Notes
11/08/2016
EQ: What forces can change
the motion and speed of an
object, and how are those
forces used to make our world
lives easier?
Starter: Next Slide
Ques
102
11/08/2016
Practice/Application:
Newton said there is a
relationship between________
Newtons 2nd LawFormulaObjects with ______ mass are
more difficult to __________.
Objects with ______ mass are
less difficult to __________.
Summary
Galelio found the objects of
different
masses_________________
Rate of gravity:
Starter
Force or No Force?
Two friends observe a piece of paper that falls from a 5
story building. The friends disagree about whether
forces were acting on the piece of paper. This is what
they say:
Jorge: “I think things have to touch in order to have a
force between them, so no forces were acting on that
piece of paper.”
Sarika: “I don’t think things have to be touching to have
force between them, so I do think forces were acting on
the piece of paper.”
Which friend do you agree with? ____________
Explain your thinking. Provide examples that support
your ideas about forces.
November 08, 2016
AGENDA
8.6 C
Students will
investigate and
describe
applications of
Newton’s by
reading and writing
during an activity.
1 Starter
2. Notes
3. Activity
4. Exit
Table of Contents
Date
Page
11/2
11/3
11/7
11/8
Lecture/ Activity/ Lab
Newton’s First Law with Poster
Newton’s First Law Lab
Newton’s First Law Lab #2
Newtons Second Law Notes
95-96
97-98
99-100
101-104
Newton’s
Second Law
TEKS 8.6A demonstrate and calculate how
unbalanced forces change the speed or
direction of an object’s motion
TEKS 8.6C investigate and describe
applications of Newton’s law of force and
acceleration
Net Force, Mass
and Acceleration
Isaac Newton
discovered one of the
most important laws
of nature; the
relationship between
net force, mass
(inertia) and
acceleration.
Newton’s second law
states that the net force
acting on a mass causes
the mass to accelerate in
the direction of the net
force.
A shorthand way of
writing this law is:
f = ma
f = force in newtons (N)
m= mass in kilograms (kg)
a = acceleration in meters per
second per second (m/s2)
Objects with more
mass are more
difficult to
accelerate.
If the same
force is applied
to two objects
with different
masses, the
one with the
smaller mass
will accelerate
more.
More mass
means less
acceleration,
unless a larger
force is applied.
Same
Forces
leads to
large
acceleration
small mass
leads to
large mass
small acceleration
Different Forces
small force
small mass
can lead to
large force
large mass
same acceleration
Falling Objects and
Newton’s 2nd Law
Galileo
Galilei, the
Italian
physicist and
astronomer,
studied
falling
objects.
He found that
when two
objects of
different
masses are
dropped, they
fell at the same
rate.
This was never fully
understood until Isaac
Newton announced his
second law of motion.
In the case of free
falling objects, the
force is equal to the
weight of the object,
which is determined
by the acceleration of
2
gravity (9.8 m/s ).
Try dropping a book
and a ball of paper.
See what happens.
Now try dropping a
piece of paper and a
book.
Most likely you will see
that the paper falls more
slowly.
Remember the book
has more weight than
the paper, so it has
more force to resist
friction from the air.
Try dropping the book
with the paper against the
lower surface of the
book.
What happens?
Now try dropping the
book with the paper
on top of the book.
How will the
accelerations of
the book and
the paper
compare?
Will they
separate and
fall
differently?
2 m/s2
m=50kg
f=
100N
m=2000 kg
f = 100N
How much force will be
required to move the
object in each picture?
.05 m/s2
What direction are the
forces applied in each
picture?
2 m/s2
m=50kg
right m=2000 kg
f=
f =
left
.05 m/s2
Will the rock and the van
accelerate at the same
rate?
No, the rock will
accelerate faster.
m=50kg
2 m/s2
f=
f =
m=2000 kg
.05 m/s2
103
Newton’s Second Law Notes
Newton’s Second Law Notes
11/8/2016
Copy Triangle here
11/08/2016
Connection: Complete calculations.
Show work. They will be graded.
1
2
3
4
Exit:
What is the force
exerted when a 5kg
bowling ball is dropped on
a toe?
104
5
6
7.
Force = mass x acceleration
Force = newtons
(N)
F
÷
m
mass = grams
(g)
÷
X
a
acceleration =
(m/s/s )or
(m/s2)
103
1. A baseball with a mass of
0.8 kg is given an acceleration
of 20m/s2. How much force
was applied to the ball?
2. A golf ball hit with a force
of 15 N travels with an
acceleration of 25 m/s2.
What is the mass of the golf
ball?
3. A force of 1500 N is
applied to a 1000 kg car.
What is the acceleration of
the car?
4. What is the mass of an
object if a force of 40 N
produces an acceleration of 4
m/s2?
5. A student tests the 104
second law of motion by
accelerating a block of ice
at a rate of 3.5 m/s2. If
the ice has a mass of
12.5 kg, what force must
the student apply to the
ice?
6. The net force acting on
a 5 kg discus is 50 N.
What is the acceleration of
the discus?
7.A 120 N force is
applied to a block,
causing an acceleration of
22.5 m/s2. What is the
mass of the block?
Science Fair Submission
Online submission at:
https://goo.gl/forms/hYDFFjjWb
zCRoYkM2