Given below are two statements: 

Assertion (A):	Young's modulus for a perfectly plastic body is zero.
Reason (R):	For a perfectly plastic body, restoring force is zero.

  

1.	Both (A) and (R) are true and (R) is the correct explanation of (A).
2.	Both (A) and (R) are true but (R) is not the correct explanation of (A).
3.	(A) is true but (R) is false.
4.	Both (A) and (R) are false.

 

A square lead slab of side 50 cm and thickness 10 cm is subject to a shearing force (on its narrow face) of $9.0\times {10}^4$ $\mathrm{N}$. The lower edge is riveted to the floor as shown in the figure below. How much will the upper edge be displaced? Shear $\mathrm{modulus}$ $\mathrm{of}$ $\mathrm{lead}$ $=$ $5.6\times {10}^9$ $\mathrm{N}$ ${\mathrm{m}}^{-\mathrm{2 }}$

1.   0.16 mm

2.   1.8 mm

3.   18 mm

4.   16 mm

A copper and a steel wire of the same diameter are connected end to end. A deforming force \(F\) is applied to this composite wire which causes a total elongation of \(1\) cm. The two wires will have:

Choose the correct option:

For an ideal liquid,

Choose the correct option:

The modulus of rigidity of the ideal liquid is:

On withdrawing the external applied force on bodies within the elastic limit, the body:

If two different types of rubber are found to have stress-strain curves as shown, then: