11.2 Springs Flashcards
What is the pull of a spring on an object holding each end of the spring called
Tension
What is the tension in a spring equal and opposite to
The force needed to extend the spring
The more a spring is stretched, the more tension there is
Who established Hooke’s law
Robert Hooke, a seventeenth century scientist
What is Hooke’s law
States that the force needed to stretch a spring is directly proportional to the extension of the spring from its natural length
Hooke’s law equation
F=kΔL
Where k is the spring constant and ΔL is the extension from its natural length L
Units:
k - Nm^-1
What happens if you change the variables of Hooke’s law
The greater the value of k, the stiffer the spring is
Hooke’s law as a graph
A straight line of gradient k through the origin
Does a spring always return to its original shape
No.
It does not if it is stretched beyond its elastic limit (limit of proportionality)
2 springs in parallel
k=kp+kq
kp being one spring and kq being the other
2 Springs in series
1/k=1/kp+1/kq
kp being one spring and kq being the other
What energy type is stored in a stretched spring
Elastic potential energy
What happens if a spring is suddenly released
The energy in the elastic store will be suddenly transferred into kinetic energy of the spring. The work done to stretch a spring by extension ΔL from its unstretched length = 1/2FΔL. The work done on the spring is stored as elastic potential energy therefore Ep=1/2FΔL
Elastic potential energy stored in a stretched spring equation:
Ep=1/2FΔL=1/2kΔL^2
