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SPRIN9S
- POTENTIAL ENERGY and.
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SIMPLE HARMONIC rY10TION
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1) \Vhat are t.'1.etwo equations
",
that des9ribe
-How mu.ch a spring
st:retches at compresses when
pushed or pulledan,
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'
.
- The potential energy stored in a.stretched:spring.
,
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.
1
2) The spring shawl). has a constant K
- (Makesure you'understandK value for springs)
= 400 N/rn.
A 1kg mass is hung 011this spring FIND-
. the stretchintl:1espring,The PE storedInthe spring.
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3) Make tWo quick graphs for the spring in question 2 ift~.f(:;liOWlo.gd.ass.es ~e placed on it.
Notethe characteristics
ofthe graphs..-" '
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20 A 20.-newtQn weight is attached to a spring,
causing it to stretch, as shown ill the diagram
b',!ow.
~-i~i--:r ~.
What is the spring constant of this spring?
(1) 0.050 N(m'
(3) 20. Nlm
(2) 0.25 N/m
(4) 40. Nlm
i)
18 A spring has a spring constant,of 120 newtons
per meter. How much potential energy is stored
in the spring as it is stretched 0.20 meter?
(1) 2.4 J
(3) 12 J
(4) 24 J
(2) 4.8 J
J)
21 :,i'ring..A has a spring constant of 140 newtons
per meter, and spring B has a spring constant of
280 newtons' peT meter. Both springs are
stretched the same distance. Compared to the
potential energy stored in spring A, the potential
energy stored in spring B is
J. the same
2 twice as great
w
3 half as great
4 four times as great
20 Which graph best represents the relationship be.
tween the elongation of an ideal spring and the
applied force?
E
t=
g9
w
FORCE
(1)
~
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S
<
;ORCE
LL
(2)
(3)
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;""CE
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as:!
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!'ORCE
(4)
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I C ''''l
.7
1-:)
student compresses the'
II~
In the diagram below, a
~
..
.
,
.
,
spring in ;. pop-up toy O.~20meter.
p, t.f '
.
If the spring has a spring constant of 340 newtons per me~~r,how much energy is being stored
in the spring?
(1) 0.068 J
(3) 3.4 J
(2) 0.14J
(4) 6.8,J'
,
([J
Which graph best represents the elastic poten- ':::',
tial energy stored in a spring (PEJ as a function :~,:':'
of its elongation, x?
.',
,','
.;.,
,
'.
.
PEs
.PESI~.
x
.x
(3 )
( 1)
PEs
PEs
x
x
(4 )
(2 )
,I'
~i,
V
The unstretched spring in the diagram belowhas
a length of 0.40 meter and spring constant k. A
weight is hung from the spring, causing it to
stretch to a length of 0.60 meter.
Unstretched
!~~~Ii<!f~W;\;;
,
Stretched
p;~~
(:':=-~..2
How many joules of elastic potential energy are
stored in this stretched spring?
(1) 0.020 X k
(3) 0.18 >~k
(2) 0.080 X k
(4) 2.0 X k
~.
1
~J:m
~
=')
@
0.60
m
.
=:~:r-L-~,Weightj
.. -',,," ''''
,
,
,,,
,
fj ;5
M ~spring isstr,etched,its elasticpoten~ energy
,(I)
decreases
"
-,"
(2) 'increases
(3) reI,Il,iunsthe' s~e
J1
A catapult witH a spring constant of 1.0 x 104newtons per meter is required to launch an airplane
from the deck of an aircraft carrier. The plane is
released when it has been 'displaced 0.50 meter
from its equilibrium position by the catapult.
The energy ,acquil"ed,by the ~lane from the
catapult d~g takeoff is approximately
(1).1.3x 103J
(2) 2.0 x 104J .
it
'
(3) 2.5x 103J
(4) 1.0 x 104J .
The' graph belOw.represents the relationship
between the forc~ app4ed to a spring and the
compression (displacement) of the spring.
AppliedForce vs. Compression
1.00.._~-0.90
!)
The graph below shows the relationship
between the elongation of a spring and the force
applied to the spring causing it to stretch.
Elongation
0.60
E 0.50
~
0.40
~
~
0.30
0
\;Y~at is the spring constant for this ?pring?
(1) 1.0 N/m
(3) 0.20 N/m
(2) 2.5 N/m
(4) 0.40 N/m
ED
vs. Applied Force
0.20
O.i 0
0
0
10. 20.
Force (N)
30.
vVhat is the spring consbmt for this spring?
(1) 0.020 N/m
(~)) 25 N/rn
(2.) 2.0 N/m
(4) 50. N/m
. .. - ...,
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BaSeyour ansv,ersto q~estions.6'6and'67 oIithe informatiQ~b~low~d. on yoci-~ow~~dg~'~f7'~)'S~cs.,
Usinga spring toy like the one shoWnin the diagrain, a physics'teiwher pushes' on the'toy, ,
, compressing
the' spring, causing the suction cup to stick to the base of the toy..,
Trials1-5
TriciJ.!
6
",'
'
'
Separated,
from base'
Not separated
from base
Suction cup,
~
..
Spring:
~
~Base
When'the teacher removes her hand, the toy pops straight up and just brushes against the
ceiling. She does this demonstration five times, always Vv'iththe same result.
vVhen the teacher repeats the demonstration for the .sixth time the toy crashes agaj.nst the .
ceiling vvithconsiderable force. The students notice that in ~is trial, the spring and toy separated from the base at the moment the spring released.
The teacher puts the toy back together, repeats the demonstration and the toy once agair:
just brushes against the. ceiling.
.66 Describe the conversions that take place between pairs of the three forms of mechanical energy, beginning
'v'\liththe work done by the teacher on the toy and ending with the formes) of energy possessed by the toy
as it hits the ceiling. [Neglect friction.]
[3]
,
67 Explain, in terms of mass and' energy, why the spring toy hits the ceiling in the si1.1:htrial and not in the
other trials.
[2]