Date:
Name:
Applying Newton's Laws of Motion
READ
ffi
In the second column of the table below, write each of Newton's three laws of motion. Use your own wording. In
the third column of the table, describe an example of each law. To find examples of Newton's laws, think about
all the activities you do in one day.
PRAGTIGeD.<-1.
When Jane drives to work, she always places her purse on the passenger's seat. By the time she gets to work,
her purse has fallen on the floor in front of the passenger seat. One day, she asks you to explain why this
happens in terrns of physics. What do you say?
2.
You are waiting in line to use the diving board at your local pool. While watching people dive into the pool
from the board, you realize that using a diving board to spring into the air before a dive is a good example of
Newton's third law of motion. Explain how a diving board illustates Newton's third law of motion.
J.
You know the mass of an object and the force applied to the object to make it move. Which ofNewton's laws
of motion will help you calculate the acceleration of the object?
4.
How many newtons of force are represented by the following amount: 3 kg'rn/sec2
Select the correct ailswer (a, b, or c) and justifu your answer.
a.6 nevrtons
b- 3 newtons
c.
1
?
newton
5.
Your shopping cart has a mass of 65 kilograms, In order to accelerate the shopping cart down an aisle at
0.3 m/sec2, what force would you need to use or apply to the cart?
6.
A small child
7.
You dribble a basketball while walking on a basketball court. List and describe the pairs of action-reaction
forces in this situation.
kilograms. The child pulls on the wagon with a force of
2 newtons. What is the acceleration of the wagon?
has a wagon
with
a mass
of
10
Name:
Date:
Newton's Second Law
REA0
ffi
Newton's second law states that the acceleration of an object is directly related to the force on it, and
inversely related to the mass of the object. You need more force to move or stop an object with a lot of mass
(or inertia) than you need for an object with less mass.
.
The formula for the second law of motion (first row below) can be rearanged to solve for mass and force.
acceleration (a)
force (F) and mass
(z)
acceleration
acceleration (a) and force
-
force
mass
("F)
acceleration (a) and mass (m)
EXAHPLE$
Dl
How much force is needed to accelerate a truck with a mass of 2,000 kilograms at a rate of 3m/secz?
F = mxa:2,000kg.+ =
sec
6,000
te.*:
6,000N
sec
What is the mass of an object that requires 15 N to accelerate it at a rate of 1.5 m/sec2?
15
-^^ - F - 15N
m:-:a 1.5m
22
sec
PnAcTlCf
ks-m
,".' -luKg
l.Sm
sec
p+--l
1.
What is the rate of acceleration of a 2,O0O-kilogram truck
moving forward?
2.
3.
4.
5.
6.
7.
What is the acceleration of a 0.30 kilogram ball that is hit with a force of 25 N?
if a force of 4,200 N is used to make it start
How much force is needed to accelerate a 68 kilogram-skier atarate of 1,.Zmlsecz?
What is the mass of an object that requires a force of 30 N to accelerate Lt arate of 5 nlsec2?
What is the force on a 1,000 kilogram-elevator that is falling freely under the acceleration of gravity only?
What is the mass of an object that needs a force of 4,500 N to accelerateit at arate of 5 mlsec2?
What is the acceleration of a 6.4 kilogram bowling ball
if a force of
12
N is applied to it?
Date:
Name:
Momentum
READ
-f,
Which is more difEcult to stop: A tractor-trailer truck barreling down the
highway at 35 meters per second, or a small two-seater sports car
traveling the same speed?
You probably guessed that it takes more force to stop a large truck than a
small car. ln physics terms, we say that the tuck has gteater momentum.
We can find momentum using this equation:
:
momentum
mass of object x velocity of object
Velocity is a term that refers to both speed and direction. For our pu{poses we will assume that the vehicles are
traveling in a straight line. In that case, velocity and speed are the same.
The equation for momentum is abbreviated like this:
p = nx x u
.
Momentum, symbolized with ap,is expressed in units of kg'm/sec; m is the mass ofthe object, in kilograms; and
v is the velocity of the object in ur/sec.
PRAGTtcaft--u
Use your knowledge about solving equations to work out the following problems:
1.
2.
3.
If the car has a mass of
4.
A beach ball is rolling in a straight line toward you at a speed of 0.5 m/sec. Its momentum is 0.25 kg'm/sec.
If
the
tuck
has a mass of 2,000 kilograms, what is its momentum? Express your answer in kg'm/sec.
1,000 kilograms, what is its momentum?
An 8-kilogram bowling ball is rolling in
is it taveling?
a straight line toward you.
If
its momentum is 16 kg'm/sec, how fast
What is the mass of the beach ball?
5.
A 4,O00-kilogram truck tavels in a straight line at 10.0 rnlsec. What is its momentum?
6.
A 1,4O0-kilogram car is also traveling in a sfiaight line. Its momentum is equal to that of the truck in the
previous question. What is the velocity of the car?
7.
Which would take more force to stop in 10 seconds: an 8.O-kilogram ball rolling in a staight line at a speed
af A.2 m/sec or a 4.0-kilogram ball rolling along the same path at a speed of 1.0 nn/sec?
8.
The momentum of a car traveling in a straight line at 20 m/sec is 24,500 kg'mlsec. What is the car's mass?
9.
A 0.14-kilogram baseball is thrown in
a straight line at a velocity of 30 m/sec. What is the momentum of the
baseball?
10. Another pitcher throws the same baseball in a straight line. Its momentum is 2.1 kg'm/sec. What is the
velocity of the ball?
11. A l.kilogmm turtle crawls in a staight line at a speed of 0.01 m/sec. What is the turtle's momentum?
Date:
's Law$ of Motion
Applying
READ
ffi
In the second column ofthe table below, write each of Newton's three laws of motion. Use your own wording. In
the third column of the table, describe an example of each law. To find examples of Newton's laws, think about
all the activities you do in one day.
everL{
t.
acfion
+WLYL
When Jane drives to worlg she always places her purse on the passenger's seat. By the time she gets to work,
her purse has fallen on the floor in front of the passenger seat. One day, she asks you to explain why this
happens in terms of physics. What do you say?
OS t'ne,rtiCu
6eff,lff5(
2.
You are waiting in line to use the diving board at your local pool. While watching people dive into the pool
from the board, you realize that using a diving board to spring into the air before a dive is a good example of
Newton's third law of motion. Exolain how a divine board illusfrates Newton's third law of motion.
€4ur-l- ilnA
J.
dPPear-Q-. -falLch on
You know the mass of an object and thb force applied to the object to make it move. Which ofNewton's laws
ofmotionwillhelp youcalculate the acceleration ofthe object?
La,W Ol
nOh;An
Lhd
4.
How many newtons of force are represented by the following amount: 3 kg'rn/sec2
Select the correct answer (a, b, or c) and justifu your answer.
a. 6 newtons
b. 3 newtons
iN=
lY.*'/*
c.
l
f= mfu
?
newton
5.
Your shopping cart has a mass of 65 kilograms. In order to accelerate the shopping cart down an aisle at
0.3 rn/sec2, what force would you need to use or apply to the cart?
6.
A small child has a wagon with a mass of
F=
bSL Z) = lg, S N
l0 kilograms. The child pulls on the wagon with a force of
2newtons.Whatistheaccelerationofthewagon?
lOCt- L=%O=
4=
O, a
b/5,
ien
fereerirthis$+ua+ioa.
Date:
Name:
Newton's Second Law
READ
ffi
Newton's second law states that the acceleration of an object is directly related to the force on it, and
inversely related to the mass of the object. You need more force to move or stop an object with a lot of mass
(or inertia) than you need for an object with less mass.
The formula for the second law of motion (first row below) can be rearranged to solve for mass and force.
force (F) and mass (m)
acceleration (a)
acceleration
-
force
mass
acceleration (a) and force (F)
acceleration (a) and mass
ExAilPLE$
(z)
Dl
How much force is needed to accelerate a truck with a mass of 2,000 kilograrns at a rate of 3mlsec2?
F = mxa = 2,000kg
What is the mass of an object that requires
"4:
sec
6,000
kg
l5 N to accelerate it
+:
sec
at a rate
6,000N
of
1.5 m/sec2?
ls l(g-+
--.-Fm:
-:
a
15N-
1.5m
-sec22
,".'
1.5m
:-,n,ruiig
sec
PRAGTIGefu--^
l.Whatistherateofacceleratiooor(,-.,-'_tirod1,.!^if,u,o,".o@usedtomakeitstan
\yjo= laaofrnmTr*.
Dfi/r"
2.WhatistheacceIeratio,,oru@Euuthatishit;;;;,,"I@,n,';'ffiu=f;3..3^/sz
moving rorward?
3.Howmuchforceisneededtoaccelerate"ffi;d!ketatao.,o@PF,bgiuz),8l.bN
!.2mlseczl
4.Whatisthemassofanobjectthatrequiresaforce"6E6acce1erateat^rate,@.2=--@,
tn= 3Dl5= ltt K4
5'W-hatistheforce*@,g)evatorthatisfall'ingfr-eeIyundqtneffi"d,',J
.--.- Lr4'goYt @QSooN
6 what is the mass or* ouj"":;lu'l
ffiaql $*Hw= g@ kg
ld ilo*: "fff:.y:
ball ir" ro.J.#qt#Hfii;
7. what is the acceleratio, orr6f,:tldfowhng
Date:
Name:
Momentum
READ
A tractor-trailer truck barreling down the
or a small two-seater sports car
Whichis
highway
traveling the same
You probably guessed that it takes
small car.ln physics terms, we say
force to stop a large truck than a
the truck has greater momentum.
We can find momentumusing this
mass of object x velocity of object
Velocity is a tenn that refers to both
traveling in a staight line. In that
and direction. For olr purposes we
locity and speed are the same.
will
assume that the vehicles are
P = mxu.
The equation for momentum is
ethrs:
Momentum, symbolized with a p, is
v is the velocity of the object in
in units of kg'm/sec; ru is the mass of the object, in kilograms; and
PBACTIC=ft'-z^
35*/s
ch- ueloul!'-35-/t
veloc.r {'1=
Use your knowledge about solving equations to work out the following problems:
1.Ifthetrrrckhasu*u,s"fdwhatirits.momentum?Expressyouranswerinkg.m/sec.
? cr;r-rc Yg I s
f_=}y*!jlf):
^
fuhat is its
momentum?
2. If the car has a mass of
Dz
3.
is
4.
itffiElins3
lb=
Bv
V=
lblg
lOoo
=
i
L35)=
Z-ls
"@d Its momentum i
fn("5) n-fi5
= _5 kg -:#
travels in a straight rine a(olGYwhrt is its momentum?
A beach ball is rolling in a staight line towld you a sped
"t
What is the mass of the beach batt? n/$=
5.
"@ck
6. a6@qffi*
.,-----m
pre@i.
\.---:--l
?il#"r
fne"rns
tr'.q 8. *"
is also traveling in a straight line. Its
What is the velocrtr 9f$3
carr ,{@
P=.*mm$ilr/s
,"*ffii,,TffJ.,"y;m#tolrfron^eLnastraightrine.atalpr
ffi ilosam
S€oil'nllbN
utffiJ;;-ft-;q, 'rf')TldLz)';\'''"r't
tl prring
ffiil:'ffi'fr
re'"ffi'-
along the
"ffipcJ
s[,
ffifrlQ:Tryfttr^
p= O.rt{(ao); qr7kj^/s
"ilpp
baseban?
-"V:A,ob*fi)l'+pogo rghA
-o*"or* [-drir L t["t orini truct iir ttre
sam.
e p.ag
,o'
=
{2"4-t\-'ztxl
T,
r4!ryrgwnatlstneca.smass,
-"^"isthemomentumorthe
(\|.,tl,tl0.Anotherpitcherthrowsthetrme&seLall'inastaight1ine.Itsmomentum,@,oatisthe
,tSvelocity of the ball?
ll'1: gulLl
2, I -- 0" fl A- A.= 2.Yrq = lS n lS"
rr. e@.E#.rtre crawls in a sraight line at a speed or@oau, is the turtle's momentum?
("or) , ,ol
-l
U^fu
f