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trasher [3.6K]
3 years ago
7

Why is an electromagnet used instead of a permanent magnet in magnetic cranes?​

Physics
2 answers:
natali 33 [55]3 years ago
8 0

Answer:

an electromagnet is a metal which has the ability to turn into a magnet on passing electricity through it .

But once the electric flow is withdrawn the circuit breaks and it no more behaves like a magnet.

but this is not so in permanent magnets

Explanation:

thus electromagnet is used in magnetic cranes bcoz their magnetism can be controlled conveniently.

ZanzabumX [31]3 years ago
4 0

Answer:

electromagnet is an artificial magnet which works on the electric current.

it has many interesting features which makes it more useful than the ordinary magnets ;

  • it can be demagnetized by stopping the current passing through it.

  • it's poles can be changed by changing the direction of current.

  • it's magnetic strength can be changed.

and electro magnet is used in cranes because big iron materials can be transported to one place to another easily by using its feature of being demagnetized easily.

<em>i hope it helped</em>.....

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A cantilever beam with a width b=100 mm and depth h=150 mm has a length L=2 m and is subjected to a point load P =500 N at B. Ca
DerKrebs [107]

Answer:

Explanation:

Given that:

width b=100mm

depth h=150 mm

length L=2 m =200mm

point load P =500 N

Calculate moment of inertia

I=\frac{bh^3}{12} \\\\=\frac{100 \times 150^3}{12} \\\\=28125000\ m m^4

Point C is subjected to bending moment

Calculate the bending moment of point C

M = P x 1.5

= 500 x 1.5

= 750 N.m

M = 750 × 10³ N.mm

Calculate bending stress at point C

\sigma=\frac{M.y}{I} \\\\=\frac{(750\times10^3)(25)}{28125000} \\\\=0.0667 \ MPa\\\\ \sigma =666.67\ kPa

Calculate the first moment of area below point C

Q=A \bar y\\\\=(50 \times 100)(25 +\frac{50}{2} )\\\\Q=250000\ mm

Now calculate shear stress at point C

=\frac{FQ}{It}

=\frac{500*250000}{28125000*100} \\\\=0.0444\ MPa\\\\=44.4\ KPa

Calculate the principal stress at point C

\sigma_{1,2}=\frac{\sigma_x+\sigma_y}{2} \pm\sqrt{(\frac{\sigma_x-\sigma_y}{2} ) + (\tau)^2} \\\\=\frac{666.67+0}{2} \pm\sqrt{(\frac{666.67-0}{2} )^2 \pm(44.44)^2} \ [ \sigma_y=0]\\\\=333.33\pm336.28\\\\ \sigma_1=333.33+336.28\\=669.61KPa\\\\\sigma_2=333.33-336.28\\=-2.95KPa

Calculate the maximum shear stress at piont C

\tau=\frac{\sigma_1-\sigma_2}{2}\\\\=\frac{669.61-(-2.95)}{2}  \\\\=336.28KPa

6 0
3 years ago
A vehicle moving along at 5m/s. What should be the constant deceleration in order to stop it within 15m?​
Oduvanchick [21]

Answer:

a = -5/6 m/s²

Explanation:

v² = u² + 2as

a = (v² - u²) / 2s

a = (0² - 5²) / 2(15)

a = -5/6 m/s²

This assumes the initial velocity was in the positive direction.

5 0
3 years ago
A positively charged insulating rod is brought close to an object that is suspended by a string. If the object is repelled away
Trava [24]

Answer

A)   Positively charged two insulating rod are brought closed to an object  they repel each other. It means the Object is positively charged. Because similar charge repel each other.

   The correct answer is Option A.

B) we know force between to charges is calculated using Formula

         F = \dfrac{kQ_1Q_2}{r^2}.......(1)

   form the given condition in the question

          F' = \dfrac{k\dfrac{Q_1}{4}\dfrac{Q_2}{4}}{(\dfrac{r}{2})^2}

          F' = \dfrac{k\dfrac{Q_1}{4}\dfrac{Q_2}{4}}{(\dfrac{r^2}{4})}

          F' = \dfrac{4}{16}\dfrac{kQ_1Q_2}{r^2}

from equation (1)

          F' = \dfrac{F}{4}

hence, the correct answer is Option C.

3 0
3 years ago
What is a personified statement?​
slamgirl [31]

Answer:

A statement about you

Explanation:

6 0
3 years ago
Read 2 more answers
What is the momentum of a cat(4kg) and running at 1.5 miles
V125BC [204]
Answer:
6kg m/s

Explanation:

Momentum = p=mxv
Momentum = mass x velocity
4kg x 1.5m= 6 kg m/s
4 0
3 years ago
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