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Airida [17]
3 years ago
15

Large capacitors can hold a potentially dangerous charge long after a circuit has been turned off, so it is important to make su

re they are discharged before you touch them. Suppose a 120 μF capacitor from a camera flash unit retains a voltage of 140 V when an unwary student removes it from the camera. If the student accidentally touches the two terminals with his hands, and if the resistance of his body between his hands is 1.8 kΩ, for how long will the current across his chest exceed the danger level of 50 mA?
Physics
1 answer:
KengaRu [80]3 years ago
8 0

Answer:

93.3x10^-3s

Explanation:

If

Resistance = 1.8 kΩ

Current = 50 mA

Capacitor = 120 μF

Voltage = 140 V

to calculate the discharge current

Applying the formula of discharge current

io=vo/R

io= 140/ 1.8x 10³

= 0.078A

to calculate the time

Applying the formula of current

io= vo/R e-t/RC

50= 140/1800e-t/RC

0.649= e-t/RC

-t/RC= ln( 0.649)

t = 0.432x 120x10^-6x 1800

t=93.3 x 10^-3seconds

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aev [14]

Answer:

A) G = m³/kg.s²

B) E = kg.m²/s²

Explanation:

A)

The given relation is:

F = Gm₁m₂/r²

where, the units of all variables are:

F = Force = kg.m/s²

m₁ = m₂ = mass = kg

r = distance = m

G = Gravitational Constant = ?

Therefore,

kg.m/s² = G(kg)(kg)/m²

(kg.m/s²)(m²/kg²) = G

<u>G = m³/kg.s²</u>

<u></u>

B)

The given equation is:

E = mc²

where, the units of all variables are:

m = mass = kg

c = speed = m/s

E = Energy = ?

Therefore,

E = (kg)(m/s)²

<u>E = kg.m²/s²</u>

This is the correct answer, which is not present in any option.

4 0
4 years ago
What is Structure C?<br><br><br> epiglottis<br><br> trachea<br><br> larynx<br><br> bronchi
finlep [7]

Answer:

it he answer is a trachea

4 0
4 years ago
A uniform bar has two small balls glued to its ends. The bar is 2.00 m long and has mass 4.00 kg, while the balls each have mass
Talja [164]

Answer:

a)1.93 kg-m^2

b) 1.45  kg-m^2

c) = 0

d) 1.15 kg-m^2

Explanation:

mass of the bar M = 4 kg

length of the bar = 2 m

mass of balls m1= m2= 0.3 kg

moment of inertia of bar I= \frac{ML^2}{12}

about an axis perpendicular to the bar through its center.

a) MOI of bar + 2×m×(L/2)^2

I= \frac{ML^2}{12}+ 2m\frac{L}{2}^2

now putting the values of m, M and L as above and solving we get

I= 1.93 kg-m^2

b) perpendicular to the bar through one of the balls

I=M\frac{L^2}{3} +mL^2

I=4\frac{2^2}{3} +0.3\times4^2= 1.45  kg-m^2

c) parallel to the bar through both balls

zero as the no mass distribution along the parallel to the bar through both balls.

d) parallel to the bar and 0.500 m from it.

I=(M+2m_1)\frac{1}{2}^2

putting values and solving we get

1.15 kg-m^2

4 0
4 years ago
The _______ is a factor that's affected by changes in the independent variable. A. dependent variable B. hypothesis C. experimen
Irina18 [472]
A. dependent variable

As the the independent variable (i.e. number of cats being sold) increases, the dependent variable (i.e. money made) will also increase. You can have 1,000,000 cats for sale and make no money, but you cannot make money without having sold some cats first.
Hope my weird example helped!
7 0
3 years ago
Read 2 more answers
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Zarrin [17]

Answer:

  • <u><em>Option A) A gas was produced.</em></u>

Explanation:

Indeed, the production of a gas is an indication that a new substance was produced as result of the reaction of the matter that constitutes the antiacid tablet and the distilled water.

A chemical reaction is a change that yields the formation of new substances (products), due to the rearrangements of the atoms of the reactants.

In a very simple form, you can represent a chemical reaction by the general equation:

  • Reactants → Products

Which means that some elements or compounds, those in the reactant side of the equation, undergo a change in which some chemical bonds are broken, the atoms separate from the original substances and combine into a new arrangement in which they form one or more different substances (products).

The option B), that the table dissapeared is not a clear evidence of a chemical change because it could have been dissolved, which is a physical change.

Also, the option C), that there was a color change, cannot be cited as an evidence of a chemical reaction, since the color is a physical property.

As for the option D, that there was a change in mass, is not a viable option, since mass cannot change either with a chemical or physical change.

3 0
3 years ago
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