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Question 1. Asked on :21 September 2020:05:30:48 PM

#### If S is the stress and Y is young's modulus of the material of a wire, what is the energy stored in the wire pere unit volume in terms of S and Y?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

Elastic potential energy stored per unit volume

½ stress × strain = ½ × stress × stressY

= S22Y.

-Answered by Shruti Srivastva On 21 September 2020:05:33:22 PM

Shruti Srivastva
Here F = 200N, l = 1 mm = 10-3m

Elastic potential energy stored in the wire,

∪ = ½ Fl = ½ × 200 × 10-3 = 0.1 J.

-Answered by Shruti Srivastva On 21 September 2020:05:28:07 PM

Question 3. Asked on :21 September 2020:05:22:11 PM

#### A wire fixed at the upper and strethches by length l by applying a force F. What is the work done in stretching the wire?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
Work done in stretching the wire,

W = 12  stetching force × increase in length

= 12  Fl.

-Answered by Shruti Srivastva On 21 September 2020:05:23:46 PM

Question 4. Asked on :21 September 2020:05:18:46 PM

#### The young's modulus of a wire of length L and radius is Y. If the length is reduced to L/2 and radius r/4, what will be its young's modulus?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
Young's modulus is a material constant. It is not affected by the change in dimensions of the wire. It will remain equal to Y.

-Answered by Shruti Srivastva On 21 September 2020:05:21:03 PM

Question 5. Asked on :21 September 2020:05:14:41 PM

#### Why are electric poles given hollow structures?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
This is because of hollow shaft is stronger than a solid shaft made from the same and equal amount of material.

-Answered by Shruti Srivastva On 21 September 2020:05:17:45 PM

Question 6. Asked on :19 September 2020:06:18:55 PM

#### The ratio stress remains constant for a small deformation. What happens to this ratio if deformation is made very large?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
When the deforming force exceeds the elastic limit, the strain increaces mare rapidly than stress. Henca the ratio of stress decreaces.

-Answered by Shruti Srivastva On 21 September 2020:05:16:10 PM

Question 7. Asked on :19 September 2020:06:15:26 PM

#### Why is the longer side of cross-section of girder used as depth?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

Depression, δ = WL34 bd3

Clearly, the depression of the girder will be small when depth d is large, because δ ∝ d-3.

-Answered by Shruti Srivastva On 19 September 2020:06:16:26 PM

Question 8. Asked on :19 September 2020:06:13:18 PM

#### A hard wire is broken by bending it repeadetly in alternating directions. Why?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
When wire is subjected to repeated alternating strains, the strength of its material decreaces and the wire breakes.

-Answered by Shruti Srivastva On 19 September 2020:06:14:27 PM

Question 9. Asked on :19 September 2020:06:10:04 PM

#### Why does a wire get heated when it is bent back and forth?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
Its deformation are beyond elastic limit. The work done aginst interomic force is no longer stord tottaly in the form of potential energy. The crystalline structure of the wire gets afected and work done is converted into heat energy.

-Answered by Shruti Srivastva On 19 September 2020:06:10:51 PM

Question 10. Asked on :19 September 2020:06:07:21 PM

#### Two identical springs of steel and copper are pulled by applyig equal force, then in which case more work will have to be done?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
Steel spring will be stretched to a lesses extent. Now more work will be done on the copper string.

-Answered by Shruti Srivastva On 19 September 2020:06:08:55 PM

Question 11. Asked on :19 September 2020:06:05:24 PM

#### What happens to work done in stretching a wire?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
Thje work done in stretching a wire is stored in it as elstic potential energy.

-Answered by Shruti Srivastva On 19 September 2020:06:06:18 PM

Question 12. Asked on :19 September 2020:06:04:00 PM

#### Why are springs made of steel and not of copper?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
Because steel stretched lesser than a copper.

-Answered by Shruti Srivastva On 19 September 2020:06:04:38 PM

Question 13. Asked on :19 September 2020:06:02:16 PM

#### Which is more elasctic ------ water or air?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

water

-Answered by Shruti Srivastva On 19 September 2020:06:03:19 PM

Question 14. Asked on :19 September 2020:06:00:05 PM

#### Write copper, stell, glass and rubber in the order of increasing coefficent of elsticity.

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

#### rubber <  glass < copper < stell.

-Answered by Shruti Srivastva On 19 September 2020:06:01:27 PM

Question 15. Asked on :19 September 2020:05:59:03 PM

#### How does young's modulus change with the rise pf temperature?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
Decrease.

-Answered by Shruti Srivastva On 19 September 2020:05:59:55 PM

Question 16. Asked on :19 September 2020:05:57:54 PM

#### What does the slope of stress versus strain graph given?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
Elasticity.

-Answered by Shruti Srivastva On 19 September 2020:05:58:48 PM

Question 17. Asked on :19 September 2020:05:56:11 PM

#### Which typr of elasticity is envolved in Tangential push on the upper face o a block?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
Modulus of rigidity.

-Answered by Shruti Srivastva On 19 September 2020:05:57:34 PM

Question 18. Asked on :19 September 2020:05:55:02 PM

#### Which type of elasticity envolved in stretching a wire?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
Young's moduls.

-Answered by Shruti Srivastva On 19 September 2020:05:55:51 PM

Question 19. Asked on :19 September 2020:05:53:58 PM

#### Which type of elasticity envolved in compressing of liquid?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
Bulk modulus.

-Answered by Shruti Srivastva On 19 September 2020:05:54:44 PM

Question 20. Asked on :19 September 2020:05:51:03 PM

#### Which type o elsticity is involved in the Compressing of gas?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
Bulk modulus.

-Answered by Shruti Srivastva On 19 September 2020:05:52:29 PM

Question 21. Asked on :19 September 2020:05:49:33 PM

#### Among solid , liquid and gas which possess the greatest bulk modulus?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

#### solid

-Answered by Shruti Srivastva On 19 September 2020:05:50:48 PM

Question 22. Asked on :19 September 2020:05:48:03 PM

#### Among solids liquids and gases, which can have all the three moduli of elasticity?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

#### solids

-Answered by Shruti Srivastva On 19 September 2020:05:49:25 PM

Question 23. Asked on :19 September 2020:05:44:37 PM

#### Stress and pressure are both forces per unit area. Then in what respect does stress differ rom pressure?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
Pressure is the external force per unit area, while stress is the internal restoring force which comes into play in a deformed body acting transversly per unit area of the body.

-Answered by Shruti Srivastva On 19 September 2020:05:45:57 PM

Question 24. Asked on :19 September 2020:05:43:33 PM

#### Is elastic limit a property of the material of the wire?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

No.

-Answered by Shruti Srivastva On 19 September 2020:05:44:26 PM

Question 25. Asked on :19 September 2020:05:42:06 PM

#### Is it is possible to double the length of a mettalic wire by applying a force over it?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
No.

-Answered by Shruti Srivastva On 19 September 2020:05:43:16 PM

Question 26. Asked on :19 September 2020:05:39:47 PM

#### State the two factor on which the modulus of elasticity depends?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

(i) Nature of the material.

(ii) Type of stress used in producing the strain.

-Answered by Shruti Srivastva On 19 September 2020:05:40:53 PM

Question 27. Asked on :19 September 2020:05:36:22 PM

#### A thick wire is suspended from a rigid support, but no load is attached to its free end. Is this wire under stress?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
Yes.

-Answered by Shruti Srivastva On 19 September 2020:05:39:29 PM

Question 28. Asked on :19 September 2020:05:32:59 PM

#### When does a body acquire a permanent set?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
When the deforming force exceeds the elastic limit, the body acqire the peramanent set.

-Answered by Shruti Srivastva On 19 September 2020:05:33:43 PM

Question 29. Asked on :19 September 2020:05:31:01 PM

#### No material is perfectly elastic. why?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
All materials undergo a change in their original state, however small it may be, after the removal o deforming force.

-Answered by Shruti Srivastva On 19 September 2020:05:31:40 PM

Question 30. Asked on :19 September 2020:05:30:02 PM

#### Write an example of perfectly plastic?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
Putty.

-Answered by Shruti Srivastva On 19 September 2020:05:30:49 PM

Question 31. Asked on :19 September 2020:05:27:55 PM

#### What is a perfectly plastic body?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
If, on removal of deforming force, a body does not regain its original confriguation even a little, then it is said to be perfectly plastic?

-Answered by Shruti Srivastva On 19 September 2020:05:28:38 PM

Question 32. Asked on :27 July 2020:12:12:35 PM

#### A body is just floating in a liquid (of equal density). What happens to the body if it is slightly pressed and released?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

The body sinks to the bottom of the liquid.

-Answered by Shruti Srivastva On 27 July 2020:12:14:26 PM

Question 33. Asked on :27 July 2020:12:08:59 PM

#### State the law of floatation.

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

According to the law of flotation, a body will float in a liquid if weight of the liquid displaced by the body is at-least equal to or greater than the weight of the body.

-Answered by Shruti Srivastva On 27 July 2020:12:10:08 PM

Question 34. Asked on :21 July 2020:05:53:31 PM

#### What does the gradual fall of barometric height indicate?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

The atmospherice pressure falls when the water vapours increase in air. This indicates the possibility of rain.

-Answered by Shruti Srivastva On 21 July 2020:05:54:38 PM

Question 35. Asked on :21 July 2020:05:44:06 PM

#### Express one atmospheric in terms of Nm-2 and bar.

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

1 atm = 1.013 x 105 Nm -2  = 1.013 x 105 Pa

= 1.013 bar.

-Answered by Shruti Srivastva On 21 July 2020:05:46:01 PM

Question 36. Asked on :20 July 2020:06:00:19 PM

#### Which of the two forces-deforming of restoring force is responsible for elastic behaviour of substance.

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva
restoring force is responsible for elastic behaviour of substance.

-Answered by Shruti Srivastva On 20 July 2020:06:01:40 PM

Question 37. Asked on :20 July 2020:05:59:09 PM

#### State Hooke's law.

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

Refer to point 15 of Glimpses .

-Answered by Shruti Srivastva On 20 July 2020:05:59:53 PM

Question 38. Asked on :20 July 2020:05:57:28 PM

#### A spiral spring is stretched by a force. What type of strain is produced in it?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

Shear strain is produced in it .

-Answered by Shruti Srivastva On 20 July 2020:05:58:30 PM

Question 39. Asked on :20 July 2020:05:54:26 PM

#### What will happen to the potential energy of the potential energy of the atoms of a solid when it is compressed? What happens when a wire is stretched ?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

Potential energy increase in both cases.

-Answered by Shruti Srivastva On 20 July 2020:05:56:48 PM

Question 40. Asked on :20 July 2020:05:50:56 PM

#### If the length of a wire increase by 1 nm under 1 kg at, what will be the increase under 100 kg wt?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

The wire will break, because the stretching force is increased beyond breaking force.

-Answered by Shruti Srivastva On 20 July 2020:05:53:23 PM

Question 41. Asked on :20 July 2020:05:47:49 PM

#### If the length of a wire increaces by 1 nm under 1 kg at, what will be the increase under 2 kg wt?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

The increase under 2 kg wt is 2mm.

-Answered by Shruti Srivastva On 20 July 2020:05:49:36 PM

Question 42. Asked on :20 July 2020:05:45:04 PM

#### What is elastic hysteresis?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

The fact that the stress-strain curve is not retracted on reversing the strain is called hysteresis.

-Answered by Shruti Srivastva On 20 July 2020:05:46:41 PM

Question 43. Asked on :20 July 2020:05:41:52 PM

#### What is elastic fatigue?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

Elastic fatigue is defined as the lass in the strength of a material caused due to repeated alternating strains to which the material is subjected.

-Answered by Shruti Srivastva On 20 July 2020:05:43:19 PM

Question 44. Asked on :20 July 2020:05:38:51 PM

#### What is elastic after effect?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

The delay on the part of the body in regaining its original configuration on the removal of the deforming force is called the elastic after effect.

-Answered by Shruti Srivastva On 20 July 2020:05:39:52 PM

Question 45. Asked on :20 July 2020:05:37:06 PM

#### What is breaking stress for a wire of unit cross-section called?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

The breaking stress for a wire of unit cross-section called Tensile strength.

-Answered by Shruti Srivastva On 20 July 2020:05:38:11 PM

Question 46. Asked on :20 July 2020:05:35:47 PM

#### Write the SI unit of modulus of rigidity?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

The SI unit of modulus of rigidity is Nm-2.

-Answered by Shruti Srivastva On 20 July 2020:05:36:38 PM

Question 47. Asked on :20 July 2020:05:31:36 PM

#### Define modulus of rigidity.

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

Modulus of rigidity is the ratio of tangenital stress of the shearing strain within the elastic limit.

-Answered by Shruti Srivastva On 20 July 2020:05:32:38 PM

Shruti Srivastva

P.E. of stretched wire = 12 Fx .

-Answered by Shruti Srivastva On 20 July 2020:05:30:37 PM

Question 49. Asked on :20 July 2020:05:25:23 PM

#### What is poisson's ration ?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

The ratio of the lateral strain to the tangenital stress to the shearing strain is called poisson's ratio.

-Answered by Shruti Srivastva On 20 July 2020:05:26:11 PM

Question 50. Asked on :20 July 2020:05:23:16 PM

#### What is the value of modulus of rigidity of an incompressible liquid?

-Added by Shruti Srivastva Physics » Mechanical Properties Of Solids

Shruti Srivastva

The value of modulus of rigidity of an incompressible liquid is zero.

-Answered by Shruti Srivastva On 20 July 2020:05:24:47 PM

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