Practise analysing deformation in solids, calculating stress, strain, Young modulus and elastic energy, and interpreting force-extension graphs and experimental evidence.
The diagram shows a beam supported on two pivots.
Which statement describes the state of the top surface X and of the bottom surface Y ?
Both X and Y are in compression.
Both X and Y are in tension.
X is in compression and Y is in tension.
X is in tension and Y is in compression.
A sample of metal is subjected to a force which increases to a maximum value and then decreases back to zero. A force-extension graph for the sample is shown.
When the sample contracts, it follows the same force-extension curve as when it was being stretched.
What is the behaviour of the metal between X and Y ?
both elastic and plastic
not elastic and not plastic
elastic but not plastic
plastic but not elastic
A force-extension graph is produced for a metal wire.
What must describe the limit of proportionality of the wire?
the point at which the wire breaks
the point beyond which Hooke's law is not obeyed
the point beyond which the wire cannot return to its original length
the point beyond which the wire starts to deform plastically
A sample of material is stretched by a tensile force to a point beyond its elastic limit. The tensile force is then reduced to zero. The force-extension graph is shown.
Which area represents the net work done on the sample?
X
X+Y
Y+Z
Z