devarshi-dt-logo

Question:

As shown in the figure, forces of 105N each are applied in opposite directions, on the upper and lower faces of a cube of side 10cm, shifting the upper face parallel to itself by 0.5cm. If the side of another cube of the same material is 20cm, then under similar conditions as above, the displacement will be:

0.37cm

0.75cm

1.00cm

0.25cm

Solution:

For same material the ration of stress to strain is same
For first cube
Stress1=105/(0.1)²
strain1=0.5/10⁻²
For second block,
stress2=105/(0.2)²
strain2=x/0.2
where x is the displacement for second block.
For same material,
stress1/strain1=stress2/strain2
From this
x=0.25cm