Tag: physics

Questions Related to physics

If stress-strain relation for volumetric change is in the form $\cfrac { \Delta V }{ { V } _{ 0 } } =KP$ where $P$ is applied uniform pressure, then $K$ stands for

physics hooke's law

  1. shear modulus

  2. compressibility

  3. Young's modulus

  4. bulk modulus

Show answer
Correct Option: B
Explanation:

Bulk modulus $=\cfrac { P }{ \Delta V/V } $
Compressibility$=\cfrac { 1 }{ Bulk\quad modulus } =\cfrac { \Delta V/V }{ P } =K\quad \quad $(Compressibility)

 Time dependent permanent deformation is called

physics hooke's law

  1. Plastic deformation

  2. Elastic deformation

  3. Creep

  4. Anelastic deformation

Show answer
Correct Option: C
Explanation:

Creep is a situation in which a component experiences deformation with time as it is put into use. Best example to illustrate this is that electrical cables are taught(tight) when they are installed but after some time they experience sagging due to self weight.

The correct option is option (c)

One end of a uniform wire of length L and of weight W is attached rigidly to a point in the roof and a weight W1 is suspended from its lower end. of S is true area of cross section of the wire, the stress in the wire at a height (3L/4) from its lower end is:

physics hooke's law

  1. [W1 + (W/4)]/S

  2. W1/S

  3. [W1 + (3W/4)]/S

  4. (W1 + W)/S

Show answer
Correct Option: C

When a steel rod of length 2m is compressed its length decreases by 0.1m. Find the work done against the compressive stress.$\left( { Y } _{ steel }=2.0\times { 10 }^{ 11 }{ Nm }^{ -2 } \right) $

physics hooke's law

  1. $2.5\times { 10 }^{ 11 } J $

  2. $1.25\times { 10 }^{ 11 } J $

  3. $5.0\times { 10 }^{ 11 } J $

  4. $7.5\times { 10 }^{ 4 } J $

Show answer
Correct Option: A

Four wires of the same material are stretched by the same load. The dimension are given below.Which of them will elongate the most?

physics hooke's law

  1. ${\text{Length}}\;100{\text{cm}},{\text{diameter}}\;1{\text{mm}}$

  2. ${\text{Length}}\;200{\text{cm}},{\text{diameter}}\;2{\text{mm}}$

  3. ${\text{Length}}\;300{\text{cm}},{\text{diameter}}\;3{\text{mm}}$

  4. ${\text{Length}}\;400{\text{cm}},{\text{diameter}}\;0.5{\text{mm}}$

Show answer
Correct Option: C

Four identical hollow cylindrical columns of steel support a big structure of mass $50,000$ kg. The inner and outer radii of each column are $30$cm and $40$cm respectively.Assuming the load distribution to be uniform. Calculate the compressional strains of each column, the young's modulus of steel is $2 \times {10^{11}}Pa$

physics hooke's law

  1. $2.78 \times {10^{ - 6}}$

  2. $3.78 \times {10^{ - 6}}$

  3. $2.78 \times {10^{ - 4}}$

  4. $3.78 \times {10^{ - 4}}$

Show answer
Correct Option: C

An elastic metal rod will change its length when it

physics hooke's law

  1. falls vertically under its weight

  2. is pulled along its length by a force acting at one end

  3. rotates about an axis at one end

  4. slides on a rough surface

Show answer
Correct Option: B,C
Explanation:

An elastic metal rod will change its length when it is pulled along its length by a force acting at one end or rotates about an axis at one end. Since, deforming force exceeds the elastic limit.

Length of a wire is increased by 1 mm on the application of a given load. If same load is applied to another wire of same material but of length and radius twice that of the first then increase in its length will be 

physics hooke's law

  1. $2 mm$

  2. $\dfrac{1}{2} mm$

  3. $4 mm$

  4. $\dfrac{1}{4} mm$

Show answer
Correct Option: B
Explanation:

$\dfrac{{stress}}{{strain}} = y$

$strain = \dfrac{{stress}}{y}$
$\dfrac{{\Delta l}}{l} = \dfrac{f}{{\Delta y}}$
$\Delta l = \dfrac{f}{y} \cdot \dfrac{l}{A}$
$\Delta l' = \dfrac{f}{y} \cdot \dfrac{{2l}}{{\pi \left( {2{r^2}} \right)}}$
$\Delta l' = \dfrac{f}{y} \cdot \dfrac{{2l}}{{4A}}$
$\Delta l' = \dfrac{{\Delta l}}{2} = \dfrac{1}{2}mm$
Hence,
option $(B)$ is correct answer.

The maximum stress developed in the rod is equal to $(N/m^{2})$.

physics hooke's law

  1. $5\times 10^{7}$

  2. $5\times 10^{8}$

  3. $4\times 10^{7}$

  4. $4\times 10^{8}$

Show answer
Correct Option: C

Which of the following is/are true about deformation of a material?

physics hooke's law

  1. Deformation capacity of the plastic hinge and resilience of the connections are essential for good plastic behavior

  2. Deformation capacity equations considering yield stress and gradient of moment

  3. Different materials have different deformation capacity

  4. All of the above

Show answer
Correct Option: D
Explanation:

In well-designed steel frame structures, inelastic deformation under severe seismic loading is confirmed in beam plastic hinges located near the beam-to-column connections. Thus, deformation capacity of the plastic hinge and resilience of the connections are essential for good plastic behavior and expected energy dissipation in steel frame structures. This essential plastic behaviour at the hinge is strongly influenced by the difference of material properties. Generally, the material properties are specified in terms of yield stress and/or ultimate strength. However, the characteristics of the materials are not defined by only these properties. Thus, the characteristics of various materials aren’t reflected in present building codes, particularly on deformation capacity classification.