6 - Definitions Flashcards
You need pair of equal and opposite ______ to alter the shape of an object.
Forces
Forces that produce extension are called _______ forces
Tensile
Forces that shorten and object are ___________ forces
Compressive
A helical spring undergoes _______ deformation when _______ forces are exerted.
[] tensile
Or
[] compressive
Hooke’s Law
True as long as elastic limit is not exceeded
The extension of the spring is directly proportional to the force applied.
F=kx
k = constant x = extension
Area under a force extension graph is equal to
Elastic Potential Energy
🔼W
F x 🔼
EPE from a force extension graph
E =
1/2 Fx
For a given spring, E is proportional to
extension ^2
The loading graph of a metal wire follows Hooke’s Law until:
The elastic limit of the wire.
Unloading graph would be identical if the elastic limit has not been reached.
Rubber bands don’t obey Hooke’s Law. The ‘loop’ formed by the loading and unloading curves is called a
Hysteresis loop
A polythene strip doesn’t obey Hooke’s Law. They suffer _______ ___________ under relatively little force.
Plastic deformation
Tensile stress is defined as:
The force applied per unit cross sectional area of the wire
ㅇ = F/A
Tensile strain is defined as:
The fractional change in the original length of the wire
ㅌ = x/L (L = original length)
