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3 years ago

12

What is the name of alfred wegener's hypothesis about moving land masses?

2 answers:

forsale [732]3 years ago

8 0

The name of Alfred Wegener's hypothesis about "moving land masses" is <u>Continental Drift</u>. He believed there was once a supercontinent which he called Pangea, which means "all land".

Umnica [9.8K]3 years ago

6 0

Pangaea; <span>the Greek word "pan" means "all" and Gaea or Gaia (or Ge) was the Greek name of the divine personification of the Earth. </span>

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A particle moves according to the equation x = 11t^2, where x is in meters and t is in seconds.

Savatey [412]

We are given the equation:

<span>x = 11t^2
</span>
We use that equation to calculate for the distance traveled.
For (a)

At t=2.20 sec,
x =53.24 meters

At t=2.95 sec,
x =95.73 meters

Velocity = (95.73 meters - 53.24<span> meters) / (2.95 s - 2.20 s ) = 56.65 m/s

</span>For (b)

At t=2.20 sec,
x =53.24 meters

At t=2.40 sec,
x =63.36 meters

Velocity = (63.36 meters - 53.24<span> meters) / (2.40 s - 2.20 s ) = 50.6 m/s</span>

4 0

3 years ago

Consider an electron with charge −e and mass m orbiting in a circle around a hydrogen nucleus (a single proton) with charge +e.

alexandr1967 [171]

Answer:

$v=\sqrt{k\frac{e^2}{m_e r}}$ , $2.18\cdot 10^6 m/s$

Explanation:

The magnitude of the electromagnetic force between the electron and the proton in the nucleus is equal to the centripetal force:

$k\frac{(e)(e)}{r^2}=m_e \frac{v^2}{r}$

where

k is the Coulomb constant

e is the magnitude of the charge of the electron

e is the magnitude of the charge of the proton in the nucleus

r is the distance between the electron and the nucleus

v is the speed of the electron

$m_e$ is the mass of the electron

Solving for v, we find

$v=\sqrt{k\frac{e^2}{m_e r}}$

Inside an atom of hydrogen, the distance between the electron and the nucleus is approximately

$r=5.3\cdot 10^{-11}m$

while the electron mass is

$m_e = 9.11\cdot 10^{-31}kg$

and the charge is

$e=1.6\cdot 10^{-19} C$

Substituting into the formula, we find

$v=\sqrt{(9\cdot 10^9 m/s) \frac{(1.6\cdot 10^{-19} C)^2}{(9.11\cdot 10^{-31} kg)(5.3\cdot 10^{-11} m)}}=2.18\cdot 10^6 m/s$

7 0

3 years ago

When we look into the sky every day we get to see the results of all the behaviors of waves. The blue color of the sky results f

mr_godi [17]

Answer:

λ = 0.4 x 10⁻⁶ m = 400 nm

Explanation:

The relationship between frequency, wavelength and speed of an electromagnetic wave is given as follows:

$c = f\lambda$

where,

c = speed of light = 3 x 10⁸ m/s

f = frequency of the light wave = 7.5 x 10¹⁴ Hz

λ = wavelength of the light = ?

Therefore,

$3\ x\ 10^8\ m/s = (7.5\ x\ 10^{14}\ Hz)\lambda\\\\\lambda = \frac{3\ x\ 10^8\ m/s}{7.5\ x\ 10^{14}\ Hz}$

<u>λ = 0.4 x 10⁻⁶ m = 400 nm</u>

4 0

3 years ago

A sample of a radioactive substance is reduced to 1.0 gram after 4 half-lives. Determine the mass of the original sample

luda_lava [24]

After 4 half-lives, there was 1 gram.

1 half-life earlier, after 3 half-lives, there must have been 2 grams.

1 half-life earlier, after 2 half-lives, there must have been 4 grams.

1 half-life earlier, after 1 half-life, there must have been 8 grams.

1 half-life earlier, when it started decaying, there must have been 16 grams. <em>(B) </em>

6 0

3 years ago

What is the wavelength of a sound wave with a frequency of 50hz (speed of sound is 342 m/s?

marysya [2.9K]

6.84m

Explanation:

According to this formula

<span>speed of wave=wavelength×frequency</span>

you have

<span>wavelength=<span>speedfrequency</span>=<span><span>342 m<span>s<span>−1</span></span></span><span>50<span>s<span>−1</span></span></span></span>=<span>6.84 m</span></span>

7 0

3 years ago