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3 years ago

Why do you think lightning is so dangerous if it strikes a person?

Physics

1 answer:

antiseptic1488 [7]3 years ago

5 0

Do you remember the old fashioned flashlights, before there were LEDs ?

They had two or three heavy batteries in the tube, and one little tiny glass light bulb in the middle of the little headlight in the front. When the batteries were fresh, that little light bulb gave out a nice bright beam of light, and drew about 0.7 Amperes from the batteries. That's the number I want you to remember for a couple of minutes: Flashlight bulb, 0.7 Amperes.

-- The wiring (nerves) that operate your heart can go haywire, and your heart can stop or go crazy, if 0.015 Amp of current or more happens to pass close by it.

-- The muscles in your arms or legs, or your diaphragm that makes you breathe, can lock up so that you can't control them, if 0.1 Amp of current or more happens to pass by them. If that current is 0.5 Amp or more and passes close to a muscle, the muscle can lock up so violently that it breaks the arm- or leg-bone that it's attached to.

Lightning is electric current flowing between a cloud and the ground. If anything is in the path it wants, it just flows right on through.

Lightning may flow in either direction ... up to the cloud or down to the ground. It really doesn't make any difference. The effects are the same, on anything it decides to flow through.

The current in a typical, average lightning bolt is 30,000 Amperes. A lot of them are bigger.

Current flowing through anything causes heat to be generated.

The more current = the more heat.

-- Lightning flowing through the wall of a house generates enough heat inside the wall to make the wall explode.

-- Lightning flowing through the juice inside a tree generates enough heat to boil the tree juice, and explode the tree.

-- Lightning flowing through the air heats a skinny tube of air so hot and so fast that the air explodes. That makes a strong sound wave in the air, that can be heard from miles away. It's called "thunder".

-- A person is made of lots of nice soft, moist, mushy stuff, water, juices, and air. A thousand Amperes flowing through it all can do a fast, efficient, complete job of heating it, boiling it, cooking it, exploding it, and tearing it to pieces.

Sounds dangerous to me.

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Calculate the kinetic energy in joules of a ball of mass 40g moving at a velocity of 4 metres per second

AfilCa [17]

Given : A ball of mass 40 g moving at a velocity of 4 m/s.
To find : Calculate the kinetic energy in joules ?
Solution :
The kinetic energy formula is given by,

where, v is the velocity v=4 m/s
m is the mass m=40 g
Convert g into kg,

Substitute the values,

Therefore, the kinetic energy is 0.32 Joules.

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2 years ago

How much energy (in Joules) is released when 12.0 g of water cools from 20.0 °C to 11.0 °C? This is a grade 10 question from the

KATRIN_1 [288]

Answer: - 452.088joule

Explanation:

Given the following :

Mass of water = 12g

Change in temperature(Dt) = (11 - 20)°C = - 9°C

Specific heats capacity of water(c) = 4.186j/g°C

Q = mcDt

Where Q = quantity of heat

Q = 12g × 4.186j/g°C × - 9°C

Q = - 452.088joule

7 0

3 years ago

At the end of the adiabatic expansion, the gas fills a new volume V₁, where V₁ > V₀. Find W, the work done by the gas on the

tino4ka555 [31]

Answer:

$W=\frac{p_0V_0-p_1V_1}{\gamma-1}$

Explanation:

An adiabatic process refers to one where there is no exchange of heat.

The equation of state of an adiabatic process is given by,

$pV^{\gamma}=k$

where,

$p$ = pressure

$V$ = volume

$\gamma=\frac{C_p}{C_V}$

$k$ = constant

Therefore, work done by the gas during expansion is,

$W=\int\limits^{V_1}_{V_0} {p} \, dV$

$=k\int\limits^{V_1}_{V_0} {V^{-\gamma}} \, dV$

$=\frac{k}{\gamma -1} (V_0^{1-\gamma}-V_1^{1-\gamma})\\$

(using $pV^{\gamma}=k$ )

$=\frac{p_0V_0-p_1V_1}{\gamma-1}$

4 0

3 years ago

An object moves along the x-axis according to the equation x = 3.00t2 – 2.00t + 3.00,

Ray Of Light [21]

Explanation:

x = 3.00 $t^{2}$ – 2.00t + 3.00,

Distance of object at 2 second,

x (t=2) = 3(4) - 2(2) +3

x (t=2) = 12-4 +3

x (t=2) = 11 m

Distance of object at 3 second,

x (t=3) = 3(9) - 2(3) +3

x (t=2) = 27 - 6 + 3

x (t=2) = 24 m

a) the average speed between t = 2.00 s and t = 3.00 s,

Average speed = $\frac{Total distance}{ Total time}$

Average speed = $\frac{x (t=2) + x (t=3)}{3}$

Average speed = $\frac{24+11}{3}$

Average speed = $\frac{35}{3}$

Average speed = 11.66 $\frac{m}{s}$

b) the instantaneous speed at t = 2.00 s and t = 3.00 s,

Instantaneous speed = $\frac{dx}{dt}$

Instantaneous speed(v) = 6t - 2 $\left \{ {{t=2} \atop {t=3}} \right.$

Instantaneous speed,v(t=2 to t=3) = 18-2-12+2

Instantaneous speed, v = 6 $\frac{m}{s}$

c) the average acceleration between t = 2.00 s and t = 3.00 s

average acceleration = $\frac{average velocity}{time}$

average acceleration = $\frac{11.66}{3-2}$

average acceleration = 11.66 $\frac{m}{s^{2} }$

d) the instantaneous acceleration at t = 2.00 s and t = 3.00 s

instantaneous acceleration = $\frac{dv}{dt}$

instantaneous acceleration =6

instantaneous acceleration = 6 $\frac{m}{s^{2} }$

e) for x =0

0 = 3.00 $t^{2}$ – 2.00t + 3.00

a = 3, b=-2, c=3

t= $\frac{-b \pm \sqrt{b^{2} - 4ac} }{2a}$

t= $\frac{2 \pm \sqrt{4 - 36} }{6}$

t= $\frac{2 \pm \sqrt{-32} }{6}$

general solution of this equation gives imaginary value. Hence, the given object is not at rest.

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3 years ago

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Which is in the Moneran kingdom? A. plants B. bacteria C. animals D. mushrooms

Stells [14]

Answer: b

Explanation:

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3 years ago