What erases the impact craters on earth and is responsible for most of the landforms that we see?

Find the magnitude of the sum of two vectors; A is 5 km , and B is 7 , when the angle btween them is 120

Dimas [21]

Answer: 6.24 km

Explanation:

Given

The magnitude of the first vector(say) $\left | a\right |=5\ km$

the magnitude of the second vector(say) $\left | b\right |=7\ km$

the angle between them is $120^{\circ}$

The resultant vector magnitude is given by

$\left | \vec{R}\right |=\sqrt{a^2+b^2+2ab\cos \theta}$

$\left | \vec{R}\right |=\sqrt{5^2+7^2+2\times 5\times 7\cdot \cos 120^{\circ}}\\\left | \vec{R}\right |=\sqrt{74-35}=\sqrt{39}\\\left | \vec{R}\right |=6.24\ km$

4 0

2 years ago

You heat up a 3.0 kg aluminum pot with 1.5 kg of water from 5 to 90o Celsius. The specific heat capacity of Aluminum is 900 J/kg

Evgen [1.6K]

Answer:

<em>765,000Joules or 765kJ</em>

Explanation:

The Quantity of heat required is expressed as;

Q = (mcΔt)al + (mcΔt)water

m is the mass

c is specific heat capacity

Δt is the change in temperature

Q = (3(900)(90-5)) + (1.5(4200)(90-5))

Q = 2700*85 + 6300*85

Q = (2700+6300)85

Q = 9000*85

<em>Hence the amount of energy needed is 765,000Joules or 765kJ</em>

8 0

2 years ago

Considering the various theories, the energy used in forming organic molecules in the primitive atmosphere could have come from

OLEGan [10]

Answer:

<h2>e. sound. </h2>

Explanation:

Such type of atmosphere in which oxygen was not present or was present in little amount is known as the primitive atmosphere and such type of atmosphere was present in the initial stage of the earth formation.
During this period, water vapor, nitrogen, hydrogen and carbon dioxide gases were present.
These gases interact with the help of energy that comes from many sources such as lightning, ultraviolet radiation, electric spark and some other.
When these inorganic molecules react in the then the formation of organic compounds takes place that becomes the basis of the organization of the life on the earth and called an organic evolution of life.

8 0

2 years ago

What do wind turbines, hydroelectric dams, and ethanol plants have in common

deff fn [24]

They all produce light and stuff

7 0

3 years ago

Which of the following is not a reason fluorescent lamps are advantageous over incandescent lamps?

cricket20 [7]

Answer;

B. Fluorescent lamps operate at a higher temperature than incandescent lamps.

Explanation;

-A fluorescent lamp, is a type of electric light (lamp) that uses ultraviolet emitted by mercury vapor to excite a phosphor, which emits visible light.

-A fluorescent lamp produces less heat, thus, it is much more efficient. A fluorescent bulb can produce between 50 and 100 lumens per watt. This makes fluorescent bulbs four to six times more efficient than incandescent bulbs.

-Fluorescent lamps operate best around room temperature. At much lower or higher temperatures, efficacy decreases.

4 0

2 years ago

Read 2 more answers