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3 years ago

A sudden discharge of static electricity during a thunderstorm is called

1 answer:

3 0

Hello
It is called lightning. Lightning in a storm occurs when there are two regions (it can be cloud-cloud or cloud-ground), one with a strong excess of positive charges and the other one with a strong excess of negative charges. The two types of charge attract each other, and then a sudden flow of charges from one region to the other occurs, which is called lightning.

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How is a nuclear power plant similar to a coal burning power plant?

Luba_88 [7]

Both are used to produce energy to be used as electricity

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3 years ago

Give an example of an energy conversion that produces an enwanted from of energy

stira [4]

An example of an energy conversion that produces an unwanted form of energy is mixing acids with water.

4 0

3 years ago

A(n) 69.8 kg astronaut becomes separated from the shuttle, while on a space walk. She finds herself 60.4 m away from the shuttle

alukav5142 [94]

Answer:

The time taken is 6.7 min

Explanation:

Using the linear momentum conservation theorem, we have:

$m_1*v_{o1}+m_2*v_{o2}=m_1*v_{f1}+m_2*v_{f2}$

when she was 60.4m from the shuttle, she has zero speed, so the initial velocity is zero.

$m_1*0+m_2*0=m_1*v_{f1}+m_2*v_{f2}\\m_1*_{f1}=-m_2*v_{f2}\\v_{f1}=-\frac{m_2*v_{f2}}{m_1}\\\\v_{f1}=-\frac{0.886kg*12m/s}{69.8kg}\\\\V_{f1}=-0.15m/s$

That is 0.15m/s in the opposite direction of the camera.

the time taken to get to the shuttle is given by:

$t=\frac{d}{v_{f1}}\\\\t=\frac{60.4m}{0.15m/s}\\\\t=403s\\t_{min}=403s*\frac{1min}{60s}=6.7min$

6 0

3 years ago

A flock of ducks is trying to migrate south for the winter, but they keep being blown off course by a wind blowing from the west

Minchanka [31]

The ducks' flight path as observed by someone standing on the ground is the sum of the wind velocity and the ducks' velocity relative to the wind:

ducks (relative to wind) + wind (relative to Earth) = ducks (relative to Earth)

or equivalently,

$\vec v_{D/W}+\vec v_{W/E}=\vec v_{D/E}$

(see the attached graphic)

We have

ducks (relative to wind) = 7.0 m/s in some direction θ relative to the positive horizontal direction, or

$\vec v_{D/W}=\left(7.0\dfrac{\rm m}{\rm s}\right)(\cos\theta\,\vec\imath+\sin\theta\,\vec\jmath)$

wind (relative to Earth) = 5.0 m/s due East, or

$\vec v_{W/E}=\left(5.0\dfrac{\rm m}{\rm s}\right)(\cos0^\circ\,\vec\imath+\sin0^\circ\,\vec\jmath)$

ducks (relative to earth) = some speed v due South, or

$\vec v_{D/E}=v(\cos270^\circ\,\vec\imath+\sin270^\circ\,\vec\jmath)$

Then by setting components equal, we have

$\left(7.0\dfrac{\rm m}{\rm s}\right)\cos\theta+5.0\dfrac{\rm m}{\rm s}=0$

$\left(7.0\dfrac{\rm m}{\rm s}\right)\sin\theta=-v$

We only care about the direction for this question, which we get from the first equation:

$\left(7.0\dfrac{\rm m}{\rm s}\right)\cos\theta=-5.0\dfrac{\rm m}{\rm s}$

$\cos\theta=-\dfrac57$

$\theta=\cos^{-1}\left(-\dfrac57\right)\text{ OR }\theta=360^\circ-\cos^{-1}\left(-\dfrac57\right)$

or approximately 136º or 224º.

Only one of these directions must be correct. Choosing between them is a matter of picking the one that satisfies both equations. We want

$\left(7.0\dfrac{\rm m}{\rm s}\right)\sin\theta=-v$

which means θ must be between 180º and 360º (since angles in this range have negative sine).

So the ducks must fly (relative to the air) in a direction 224º relative to the positive horizontal direction, or about 44º South of West.

8 0

3 years ago

A car stands from rest and attains a speed of 20 m/s in 10 s. What distance will it cover ?

sashaice [31]

Answer:

100m

Explanation:

100m

s=ut+1/2at^2

s= unknown, u=0, a=2, t=10

s=0*10+1/2(2)(10)^2

s=1/2(2)(100)

s=1(100)

displacement = 100 meters

4 0

3 years ago