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2 years ago

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When were Earth’s landmasses first recognizable as the continents we know today? 10 million years ago 135 million years ago 180

million years ago 300 million years ago

2 answers:

Bess [88]2 years ago

6 0

Answer:

b

Explanation:

i took the test

cluponka [151]2 years ago

6 0

Answer:

b 135 million years

Explanation:

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If a cat falls off a ledge, the Earth pulls the cat to the ground with the force of gravity. According to Newton's Third Law the

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2 years ago

Read 2 more answers

Electromagnetic radiation is emitted when a charged particle moves through a medium faster than the local speed of light. This r

alexandr1967 [171]

Answer:

to create the particle the speed must be greater than 2.25 10⁸ m / s

Explanation:

In this exercise we must use the relation of the index of refraction with the speed of light in a vacuum and a material medium

n = c / v

where c is the speed of light in the vacuum, v the speed of light in the material medium and n the ratio of rafraccio

in this case they give us that the medium matter water them that has a refractive index of

n = 1,333

we clear

v = c / n

let's calculate

v = 3 10⁸ / 1,333

v = 2.25 10⁸ m / s

to create the particle the speed must be greater than 2.25 10⁸ m / s

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2 years ago

A circular pipe of 25-mm outside diameter is placed in an airstream at 25C and 1-atm pressure. The air moves in cross flow over

kifflom [539]

Answer:

f_D = =3.24 N/m

Explanation:

data given

properties of air $\nu\ of air =19.31*10^{-6} m2/s$

$\rho = 1.048 kg/m3$

k = 0.0288 W/m.K

WE KNOW THAT

Reynold's number is given as

$Re =\frac{VD}{\nu}$

$= \frac{ 15*0.025}{19.31*10^{-6}}$

= 1.941 *10^4

drag coffecient is given as

$C_D = \frac{f_D}{A_f\frac{\rho v^2}{2}}$

solving for f_D

$f_D = C_D A_f*\frac{\rho v^2}{2}$

$=C_D D*\frac{\rho v^2}{2}$

Drag coffecient for smooth circular cylinder is 1.1

therefore Drag force is

$f_D = 1.1*0.025 *\frac{1.048*15^2}{2}$

f_D = =3.24 N/m

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2 years ago

A bucket of mass M (when empty) initially at rest and containing a mass of water is being pulled up a well by a rope exerting a

Naily [24]

Answer:

$V=\dfrac{PT}{m}\ ln\dfrac{M+m}{M}-gT$

Explanation:

Given that

Constant rate of leak =R

Mass at time T ,m=RT

At any time t

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So the total mass in downward direction=(M+Rt)

Now force equation

(M+Rt) a =P- (M+Rt) g

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$a=\dfrac{dV}{dt}$

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This is the velocity of bucket at the instance when it become empty.

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2 years ago