Elastic P.E. - work stored in a deformed spring

a) General Equation  

 

PEs = Fx

F = Average Force needed to deform spring

 

x = distance deformed (stretch or compress)

 

 

slapshot

Noble and Greenough School HS

 

 

Ideal Spring

St. Mary's H.S.

Full Screen Version

 

 

b)  Hooke's Law - force needed to deform an ideal spring, a given amount is directly proportional to its displacement (deformation)

 

Graphic from Learning-Connections Clipart

 

Robert Hooke

Robert Hooke: Victim of Genius

'Newton's bitter rival'

Robert Hooke Website

 





 

Ex) Ideal Spring

 

F
(Force to Deform) (N)
X
(distance deformed) (m)

2.0

.30
4.0



.60
6.0

 



.90
8.0






1.2

 




Hooke's Law
University of Colorado - PhET

 

 

slope = F/x

x = stretch

 

 

c) Spring Constant, Ideal Spring

 

- quantifies stiffness
of a spring

 

K = F (N)
X (m)

 

What is the spring constant of the spring that produced the data? above?

 

 F
(Force to
 Deform)
(N)
X
(distance deformed)
(m)
2  .30
4  .60
6  .90
8   1.2



k = 2.0 N
.30 m

 

 

 

k = 6.7 N/m

 

 

 

Which is the stiffer spring?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Spring A is the stiffer spring.

More force is required
for the same stretch

 

 

 

 

Ex) Plots and K

 

 

 

 

 

Pick any point on the line

 

K = F (N)
X (m)



K = 20. N
.40 m 

 

 

 

K = 50. N/m

 

 

d) Elastic P.E. = area of triangle under F vs x graph

 

 

 

PEs = (½)basexheight

 

PEs = 6 Joules

 

 

 

 

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