Behaviour of springs Flashcards
By compressive force, the spring…
is squashed.
By tensile force, the spring…
is stretched.
Restoring force is when…
spring applies equal but opposite force on the person applying the force.
Hook’s law states:
The extension of spring is directly proportional to the force applied until the limit of proportionality is not exceeded.
F=
kx - spring constant x extension
Limit of proportionality is a point…
beyond which behaviour no longer obeys Hook’s law.
Elastic limit is a point…
beyond which the spring will no longer return to its original shape when the force is removed.
Elasticity is…
the ability to regain shape after deforming forces are removed.
The Young modulus is…
the ration of stress to strain for a material obeying Hook’s law.
Stress=
F/A
Strain=
extension/length
Young modulus=
stress/strain
Stress-strain graph:
- a gradient is a young modulus
- the area represents the energy absorbed by the material
The yield point is large…
increase in the extension of a material when the stress is increased beyond the elastic limit.
UTS is…
Ultimate tensile stress, maximum stress experienced before breaking (per unit C.S.A.)
Plastic deformation is…
deformation that is permanent after removal of the load.
A thick rod is harder to compress as…
the surface area is larger-more stress must be applied.
Increase in young modulus or A causes…
decrease in ΔL
Increase in original length causes…
increase in ΔL
Stiffness reflects…
how difficult is to change the shape of a material.
Strength is…
the maximum tensile stress before breaking.
Toughness is energy…
needed to break material(area under a stress-strain curve)
Elastic potential energy is…
energy stored in a body due to a load causing deformation.
Work must be done to store…
EPE.
EPE=
F x extension
Work done can be found as an area under…
force/distance graph.
Work done(spring)=
0.5 x k x extention2
Springs in series:
k= 1/k1 + 1/k2
Springs in parallel:
k=k1 + k2
