Which is the only mechanism that can introduce new alleles in a gene pool? genetic drift random mating mutation

Five hundred million years ago, basaltic lava flowed in an area now known as Monticello, the historic home of Thomas Jefferson.

aev [14]

Explanation:

Igneous - metamorphic - sedimentary

A rock cycle provides the cyclic transformation of one rock type to another in nature.

There are three main types of rock involved in the rock cycle;

igneous rocks are derived from the cooling and solidification of molten magma
metamorphic rocks are changed rocks subjected to intense pressure and temperature
sedimentary rocks are derived from rock sediments that have been lithified.

The history of the rock in Monticello begins with igneous rock formation. Basalt is an igneous rock that forms from the cooling and solidification of molten magma. Under intense pressure and temperature regimes, they are changed to metamorphic rocks.

Agents of denudation such as wind, water and glacier weathers the rock and disintegrates it. They are then carried into basins where they are deposited. Here they form sedimentary rock.

The process still goes on as the sedimentary rock gets taken into depth, they can either melt to form igneous rock or be changed to metamorphic rocks.

learn more:

metamorphic process brainly.com/question/869769

sedimentary rocks brainly.com/question/9131992

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5 0

3 years ago

24. An elevator is moving vertically up with an acceleration a. The force exerted on the floor by a passenger of mass m is

Wewaii [24]

Given :-

An elevator is moving vertically up with an acceleration a.

To Find :-

The force exerted on the floor by a passenger of mass m .

Solution :-

As the man is in a accelerated frame that is non inertial frame , we would have to think of a pseudo force .

The direction of this force is opposite to the direction of acceleration the frame and its magnitude is equal to the product of mass of the concerned body with the acceleration of the frame .

For the FBD refer to the attachment . From that ,

$\implies Weight_{apparent}= mg + ma$

Hence option d is correct choice .

I hope this helps .

3 0

2 years ago

A factory worker pushes a 30.0-kg crate a distance of 4.5 m along a level floor at constant velocity by pushing horizontally on

SIZIF [17.4K]

(a) 73.5 N

The velocity of the crate is constant: this means that the acceleration is zero (a=0), so according to Newton's second law

$\sum F = ma$

the resultant of the forces must be zero: $\sum F = 0$ (1)

The motion is along the horizontal direction, so we are only interested in the forces acting along this direction. There are two of them:

$F$ , the push applied by the worker

$F_f=-\mu mg$ , the force of friction, with $\mu=0.25$ being the coefficient of friction, $m=30.0 kg$ being the mass of the crate, and $g=9.8 m/s^2$ . The negative sign is due to the fact that the friction acts in the opposite direction to the motion. Eq.(1) then becomes

$F-\mu mg=0\\F=\mu mg=(0.25)(30.0 kg)(9.8 m/s^2)=73.5 N$

So, this is the force that the worker must apply.

(b) 330.8 J

The work done by the pushing force of the worker on the crate is given by:

$W=Fd cos \theta$

where

F = 73.5 N is the force

d = 4.5 m is the displacement

$\theta=0^{\circ}$ is the angle between the direction of the force and the displacement (0 degrees, since they are in same direction)

Substituting, we have

$W=(73.5 N)(4.5 m)(cos 0^{\circ})=330.8 J$

(c) -330.8 J

To calculate the work done by friction, we apply the same formula:

$W=F_f d cos \theta$

where

$F_f = \mu mg=(0.25)(30.0 kg)(9.8 m/s^2)=73.5 N$ is the magnitude of the force of friction

d = 4.5 m is the displacement

$\theta=180^{\circ}$ is the angle between the direction of the force of friction and the displacement (it is 180 degrees since the two are into opposite directions)

Substituting, we find

$W=(73.5 N)(4.5 m)(cos 180^{\circ})=-330.8 J$

So, the work done by friction is negative.

(d) 0 J

As before, the work done by any force on the crate is

$W=F_f d cos \theta$

We notice that both gravity and normal force are perpendicular to the displacement: therefore, $\theta=90^{circ}$ , and so

$cos \theta=0$

which means that the work done by both forces is zero.

(e) 0 J

The total work done on the crate is the sum of the work done by the four forces acting on it, so:

$W=W_{push} + W_{friction}+W_{gravity}+W_{normal}=330.8J-330.8J+0+0=0$

And this is in accordance with the work-energy theorem, which states that the variation of kinetic energy of the crate is equal to the work done on it: since the crate is moving at constant velocity, its variation of kinetic energy is zero, as well as the work done on it.

5 0

3 years ago

How do you know that a chemical change has happened

Elodia [21]

Answer:

theres is many states of chemical change but its not exaclty the same as physical the appearence might change alittle but chemical like frying a egg is a chemical change because a change of materials into another, new materials with different properties and one or more than one new substances are formed and the subtance changeing or the materials can show chemical changed happened you cant always see it but touching too like heat energy can show a chemical change

Explanation:

i hope this helps and keep ur grades up :)

6 0

1 year ago

Read 2 more answers

The boat is travelling at a constant velocity.

raketka [301]

the friction forces are smaller than the forward force

5 0

3 years ago