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3 years ago

Which common house hold items will turn litmus paper blue

Physics

1 answer:

prohojiy [21]3 years ago

6 0

Answer:

Toothpaste

Explanation:

When red litmus paper turns blue, it's a clear indicator that the solution or item where it was put is basic. The most common household item which is known to be basic is toothpaste. Experimental studies show that when you put red litmus paper into toothpaste solution, it turns blue.

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What is the force per unit area at this point acting normal to the surface with unit nor- Side View √√ mal vector n = (1/ 2)ex +

Mumz [18]

Complete Question:

Given $\sigma = \left[\begin{array}{ccc}10&12&13\\12&11&15\\13&15&20\end{array}\right]$ at a point. What is the force per unit area at this point acting normal to the surface with $\b n = (1/ \sqrt{2} ) \b e_x + (1/ \sqrt{2}) \b e_z$ ? Are there any shear stresses acting on this surface?

Answer:

Force per unit area, $\sigma_n = 28 MPa$

There are shear stresses acting on the surface since $\tau \neq 0$

Explanation:

$\sigma = \left[\begin{array}{ccc}10&12&13\\12&11&15\\13&15&20\end{array}\right]$

equation of the normal, $\b n = (1/ \sqrt{2} ) \b e_x + (1/ \sqrt{2}) \b e_z$

$\b n = \left[\begin{array}{ccc}\frac{1}{\sqrt{2} }\\0\\\frac{1}{\sqrt{2} }\end{array}\right]$

Traction vector on n, $T_n = \sigma \b n$

$T_n = \left[\begin{array}{ccc}10&12&13\\12&11&15\\13&15&20\end{array}\right] \left[\begin{array}{ccc}\frac{1}{\sqrt{2} }\\0\\\frac{1}{\sqrt{2} }\end{array}\right]$

$T_n = \left[\begin{array}{ccc}\frac{23}{\sqrt{2} }\\0\\\frac{27}{\sqrt{33} }\end{array}\right]$

$T_n = \frac{23}{\sqrt{2} } \b e_x + \frac{27}{\sqrt{2} } \b e_y + \frac{33}{\sqrt{2} } \b e_z$

To get the Force per unit area acting normal to the surface, find the dot product of the traction vector and the normal.

$\sigma_n = T_n . \b n$

$\sigma \b n = (\frac{23}{\sqrt{2} } \b e_x + \frac{27}{\sqrt{2} } \b e_y + \frac{33}{\sqrt{2} } \b e_z) . ((1/ \sqrt{2} ) \b e_x + 0 \b e_y +(1/ \sqrt{2}) \b e_z)\\\\\sigma \b n = 28 MPa$

If the shear stress, $\tau$ , is calculated and it is not equal to zero, this means there are shear stresses.

$\tau = T_n - \sigma_n \b n$

$\tau = [\frac{23}{\sqrt{2} } \b e_x + \frac{27}{\sqrt{2} } \b e_y + \frac{33}{\sqrt{2} } \b e_z] - 28( (1/ \sqrt{2} ) \b e_x + (1/ \sqrt{2}) \b e_z)\\\\\tau = [\frac{23}{\sqrt{2} } \b e_x + \frac{27}{\sqrt{2} } \b e_y + \frac{33}{\sqrt{2} } \b e_z] - [ (28/ \sqrt{2} ) \b e_x + (28/ \sqrt{2}) \b e_z]\\\\\tau = \frac{-5}{\sqrt{2} } \b e_x + \frac{27}{\sqrt{2} } \b e_y + \frac{5}{\sqrt{2} } \b e_z$

$\tau = \sqrt{(-5/\sqrt{2})^2 + (27/\sqrt{2})^2 + (5/\sqrt{2})^2} \\\\ \tau = 19.74 MPa$

Since $\tau \neq 0$ , there are shear stresses acting on the surface.

3 0

3 years ago

If a ball is dropped from a height (H) its velocity will increase until it hits the ground (assuming that aerodynamic drag due

mario62 [17]

Answer:

9.801 m/s²

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity = 39 ft/s

s = Displacement = 720 cm = 7.2 m

a = Acceleration

Converting to m/s

$39\ ft/s=\frac{39}{3.281}=11.88\ m/s$

Equation of motion

$v^2-u^2=2as\\\Rightarrow a=\frac{v^2-u^2}{2s}\\\Rightarrow a=\frac{11.88^2-0^2}{2\times 7.2}\\\Rightarrow a=9.801\ m/s^2$

Acceleration of the ball is 9.801 m/s²

5 0

3 years ago

What additions must you make to the cell for it to generate a standard emf?

xeze [42]

Answer: Addition of salt bridge

To generate a standard electromotive force, an addition of salt bridge is essential to help maintain electrical neutrality within the internal circuit and prevent the cell from rapidly running its reaction to equilibrium.
In addition, salt bridge contains potassium sulfate, an inert electrolyte where its ions will diffuse into the separate half-cells to stabilize the building charges at the electrodes and produce electricity.

4 0

4 years ago

At what speed must a 0.6 kg stone be thrown in order that it has a relativistic mass of 0.76 kg? (c = 3.00 x 10^8 m/s) (A) 0.39

exis [7]

Explanation:

It is given that,

Relativistic Mass of the stone, m₀ = 0.6

Mass, $m=0.76\ kg$