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3 years ago

Tudy the images about geologic time.

Physics

1 answer:

Fittoniya [83]3 years ago

6 0

Answer:

The first flowering plants appeared in the Mesozoic era, not the Paleozoic era

Explanation:

The Mesozoic era is well known and most famous because of the rule of the dinosaurs which were the dominant animals for most of this are. Also, it is the era in which the mammals appeared, though they lived in the shadows of the dinosaurs and only became dominant after their extinction. Another important evolution that took place and is not mentioned very often is the appearance of the first flowering plants. This was a revolutionary trait for the plants, and it helped them to survive in the changing climate on Earth. Soon this trait enabled this type of plants to spread out significantly and to become one of the most dominant organisms on the planet in the following era.

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What phenomenon reduces the adverse effects and pressure imposed by solar wind on earth?

inessss [21]

Answer:

The earths magnetic field

Explanation:

3 0

2 years ago

Determine the magnitude and direction of the force on a 200 m power line carrying a current of 5.0-A due west in a magnetic fiel

bogdanovich [222]

Answer:

Explanation:

l = 200 m

i = 5 A west

B = 6 micro Tesla direction 30 degree north of east

angle between length vector and the magnetic field vector = 180 - 30 = 150 degree

Write the length and the magnetic field in the vector form

$\overrightarrow{l}=- 200 \widehat{i}metre$

$\overrightarrow{B}= 6\times 10^{-6}\left ( Cos30\widehat{i}+Sin30\widehat{j} \right )Tesla$

$\overrightarrow{B}=\left ( 5.2\widehat{i}+3\widehat{j} \right )\times 10^{-6}Tesla$

$\overrightarrow{F} = i \overrightarrow{l}\times \overrightarrow{B}$

$\overrightarrow{F} = 5\times \left ( -200\widehat{i} \right )\times \left ( 5.2\widehat{i}+3\widehat{j} \right )\times 10^{-6}$

$\overrightarrow{F} =- 3\times 10^{-3}\widehat{k}Newton$

Thus, the magnitude of force is 3 x 10^-3 newton and it is directed towards negative z axis direction.

7 0

2 years ago

A box of mass 12 kg is at rest on a flat floor. The coefficient of static friction between the box and floor is 0.42. What is th

Oxana [17]

The maximum static force that can be applied is equal to the normal force*the frictional force. the normal force on the box is equal to mg since the floor is flat using 9.81m/s^2 for gravity 12kg*9.81m/s^2 = 118N multiplying the normal force by the frictional force you get a 118*.42= 49.6N so overcome the force of static friction on the box a minimum of 49.6N would need to be applied.

5 0

3 years ago

Read 2 more answers

Consider a string with a length of (47.5 A) cm tied at both end (like on a stringed instrument). If the frequency of the first h

zubka84 [21]

To solve this problem it is necessary to apply the concepts related to wavelength as a function of frequency and speed, as well as to determine the wavelength as a function of length.

From the harmonic vibration generated we know that the total length of the string will be equivalent to a half of the wavelength, that is

$L = \frac{\lambda}{2} \rightarrow \lambda = 2L$

Where,

$\lambda =$ Wavelength

Therefore the wavelength for us would be,

$\lambda = 2*47.5cm = 95cm = 0.95m$

From the relationship of speed, frequency and wavelength we know that

$\lambda = \frac{v}{f} \rightarrow v = \lambda f$

$v = (0.95m)(245Hz)$

$v = 232.75 m/s$

Therefore the speed of the wave is 232.75m/s

4 0

3 years ago

A car is driven 225 km west and then 98 km southwest (45).

slava [35]

Sum the vector components: Dx = 225* Cos(180)+ 78*Cos(225)= -280.154 km Dy = 225* Sin(180)+ 78*Sin(225) = -55.154 km displacement: Sqrt(Dx^2+Dy^2) = 285.532 km Arctan(Dy/Dx) = 191.137degrees CCW OR: 11.137 degrees South of West

4 0

3 years ago

Read 2 more answers