The process of soil formation involves the following steps: Accumulation of materials, leaching and losses (because of weather factors particles are leached and eroded away or taken up from the soil by plants), Transformation and illluviation (the chemical weathering<span> of silt, sand, and the formation of clay minerals as well as the change of organic materials into decay resistant organic matter), p</span>odsolisation and translocations (strong acidic solutions breakdown the clay minerals). From the given options soil formation involves both <span>physical and chemical weathering of rocks. Correct answer:D</span>
Efficiency = useful energy out / total energy in x 100
= 100/400 x 100
=0.25 x 100
= 25%
25%
the polluted urban environment affects the health and quality of life
A) d. 10T
When a charged particle moves at right angle to a uniform magnetic field, it experiences a force whose magnitude os given by

where q is the charge of the particle, v is the velocity, B is the strength of the magnetic field.
This force acts as a centripetal force, keeping the particle in a circular motion - so we can write

which can be rewritten as

The velocity can be rewritten as the ratio between the lenght of the circumference and the period of revolution (T):

So, we get:

We see that this the period of revolution is directly proportional to the mass of the particle: therefore, if the second particle is 10 times as massive, then its period will be 10 times longer.
B) 
The frequency of revolution of a particle in uniform circular motion is

where
f is the frequency
T is the period
We see that the frequency is inversely proportional to the period. Therefore, if the period of the more massive particle is 10 times that of the smaller particle:
T' = 10 T
Then its frequency of revolution will be:

Answer:
<em>2.753*10^-11N</em>
Explanation:
According to Newton's law of gravitation, the force between the masses is expressed as;
F = GMm/d²
M and m are the distances
d is the distance between the masses
Given
M = 3.71 x 10 kg
m = 1.88 x 10^4 kg
d = 1300m
G = 6.67 x 10-11 Nm²/kg
Substitute into the formula
F = 6.67 x 10-11* (3.71 x 10)*(1.88 x 10^4)/1300²
F = 46.52*10^(-6)/1.69 * 10^6
F = 27.53 * 10^{-6-6}
F = 27.53*10^{-12}
F = 2.753*10^-11
<em>Hence the gravitational force between the asteroid is 2.753*10^-11N</em>
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