The lower surface of a cube is fixed. On its upper surface,a force is applied at an angle of $30^{\circ}$ from its surface. The change will be of the type:

If a string, suspended from the ceiling, is given a downward force $F_1$, its length becomes $L_1$. Its length becomes $L_2$ if the downward force is $F_2$. What is its actual length?

Explain longitudinal stress.

One end of a uniform wire of length $L$ and weight $W$ is attached rigidly to a point in the roof,and a weight $W_1$ is suspended from its lower end. If $S$ is the area of cross-section of the wire,the stress in the wire at a height $3L/4$ from its lower end is

The load versus elongation graphs for four wires of same length and made of the same material are shown in the figure. The thinnest wire is represented by the line

The elastic limit of a metal is $\frac{400}{\pi} \text{ MPa}$. If a rod of this metal is to support a $484 \text{ N}$ load without exceeding its elastic limit, the minimum diameter of the rod is: (in $\text{ mm}$)