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3 years ago

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What is SI system and SI unit?

1 answer:

Novay_Z [31]3 years ago

7 0

Answer:

nternational System of Units (SI), French Système International d'Unités, international decimal system of weights and measures derived from and extending the metric system of units. Adopted by the 11th General Conference on Weights and Measures (CGPM) in 1960, it is abbreviated SI in all languages.

Explanation:

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Starting from zero, the electric current takes 2 seconds to reach half its maximum possible value in an RL circuit with a resist

Leno4ka [110]

Answer:

time=4s

Explanation:

we know that in a RL circuit with a resistance R, an inductance L and a battery of emf E, the current (i) will vary in following fashion

$i(t)=\frac{E}{R}(1-e^\frac{-t}{\frac{L}{R}})$ , where $i$ max= $\frac{E}{R}$

Given that, at i(2)= $\frac{imax}{2} =\frac{E}{2R}$

⇒ $\frac{E}{2R}=\frac{E}{R}(1-e^\frac{-2}{\frac{L}{R}})$

⇒ $\frac{1}{2}=1-e^\frac{-2}{\frac{L}{R}}$

⇒ $\frac{1}{2}=e^\frac{-2}{\frac{L}{R}}$

Applying logarithm on both sides,

⇒ $log(\frac{1}{2})=\frac{-2}{\frac{L}{R}}$

⇒ $log(2)=\frac{2}{\frac{L}{R}}$

⇒ $\frac{L}{R}=\frac{2}{log2}$

Now substitute $i(t)=\frac{3}{4}imax=\frac{3E}{4R}$

⇒ $\frac{3E}{4R}=\frac{E}{R}(1-e^\frac{-t}{\frac{L}{R}})$

⇒ $\frac{3}{4}=1-e^\frac{-t}{\frac{L}{R}}$

⇒ $\frac{1}{4}=e^\frac{-t}{\frac{L}{R}}$

Applying logarithm on both sides,

⇒ $log(\frac{1}{4})=\frac{-t}{\frac{L}{R}}$

⇒ $log(4)=\frac{t}{\frac{L}{R}}$

⇒ $t=log4\frac{L}{R}$

now subs. $\frac{L}{R}=\frac{2}{log2}$

⇒ $t=log4\frac{2}{log2}$

also $log4=log2^{2}=2log2$

⇒ $t=2log2\frac{2}{log2}$

⇒ $t=4$

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3 years ago

Які лампочки у схемі з'єднані<br> паралельно?

alekssr [168]

Answer:

I don't understand please interpret

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3 years ago

A 50 kg archer standing on frictionless ice shoots a 100g arrow at a speed of 100 m/s what uis the recoild pseed of the archer?

nexus9112 [7]

Answer:

v= 0.2 m/s

Explanation:

Given that

m₁ = 50 kg

m₂ = 100 g = 0.1 kg

u =10 0 m/s

If there is no any external force on the system then the total linear momentum of the system will be conserve.

Initial linear momentum = Final momentum

m₁u₁ + m₂ u₂ =m₂ v₂ +m₁v₁

50 x 0 + 0.1 x 100 = 50 v + 0

0+ 10 = 50 v

$v=\dfrac{10}{50}\ m/s$

v= 0.2 m/s

Therefore the recoil speed will be 0.2 m/s.

7 0

3 years ago

A clothes dryer uses about 9 amps of current from a 240 volt line. How much power does it use?

Basile [38]

240 x 9 = power
power= 2160 watts

4 0

4 years ago

Read 2 more answers

Atwood machine. A 20kg box and a 30kg crate are attached to the two ends of a massless string that passes over a massless fricti

Verdich [7]

Answer with Explanation:

We are given that

$m_1=20 kg$

$m_2=30 kg$

We have to find the acceleration of the system and the tension in the string.

$30g-T=30a$ ...(1)

$T-20g=20a$

$T=20a+20g$ ...(2)

Using equation (2) in equation (1)

$30g-(20a+20g)=30a$

$30g-20a-20g=30a$

$10g=30a+20a=50a$

$a=\frac{10g}{50}=\frac{10\times 9.8}{50}=1.96 m/s^2$

Where $g=9.8m/s^2$

Using the value of a in equation (2)

$T=20(a+g)=20(1.96+9.8)=235.2 N$

5 0

3 years ago