For numbers 2 and 3, which one is compression and which one is rarefaction?

One block rests upon a horizontal surface. A second identical block rests upon the first one. The coefficient of static friction

goblinko [34]

Answer:

The magnitud of the force is 124.8N.

Explanation:

First we have to find the value of the static friction coefficient, when the external force F is applied to upper block (i will call it A Block) we have a free body diagram as the one shown in the figure i attached, so since this block has no aceleration in any direction the force F should be equal to the friction force between A and B block, one we noticed this we can use the equation for the Friction force to find the coefficient:

$0=F-FrictionAB$

$F=FrictionAB=Nab*$ μs

and again, since the block has no acceleration the normal between A and B block should be equal to the weigth of the first block, so we have:

$0=Nab-W$

$Nab=W=mg$

replacing this we have:

$F=$ μs $*Nab=$ μs* $mg=41.6N$

and μs $=41.6N/(mg)$

now it's time to see the free body diagram for the b block, if we now apply the F force to the B block the diagram should look like in the figure.

the color of the arrow gives you an idea of where the force comes from, the blue ones comes from the B block, the red ones from the A block and the brown ones from the ground.

now for the B block you can see two friction forces, one for the ground and one for the A block, both of these directed bacwards, and two normal forces, again one for the ground and one for the A block but the normal force for the A block is aiming downwards.

again we use the fact that the block is not accelerating in any direction so the sum of the forces in x and y direction have to be 0, so:

$F-Friction1(ground)-Friction2(AB)=0$

This is the new external F force that we are looking for:

$F=Friction1(ground)+Friction2(AB)$

we know Friction2(AB) because we found that in the previous block so:

$F=Friction1(ground)+mg$ *μs

for the other friction we have to use the equation:

$Friction(ground)=N(ground)$ *μs

from y axis we have:

$N(ground)-w-Normal(AB)=0$

$N(ground)=w+Normal(AB)$

we found the value of Normal(AB) with the previous block so:

$N(ground)=mg+mg=2mg$

and:

$Friction(ground)=2mg$ *μs

$F=Friction(ground)+mg$ *μs

$F=2mg$ *μs+μs* $mg=3mg$ *μs

and since: μs* $mg=41.6N$

the new F force would be:

$F=3mg$ *μs $=41.6*3=124.8N$

4 0

3 years ago

What is the motional kinetic energy of a 25 kg object moving at a speed of 10 m/s?

Soloha48 [4]

1250kgm²/s is the motional kinetic energy of a 25kg object moving at a speed of 10m/s

Kinetic energy of an object is defined as the energy which is possessed when that is in motion. It is the energy of the kinetic mass of an object. Kinetic energy is never negative and is a scalar quantity. That is, it shows only size, not orientation.

Given to us

Mass of the object, m=25kg

Velocity of the object, v=10m/s

K.E=1/2x25x10²

=1250

Kinetic energy is directly proportional to the mass and velocity squared (K.E.) of an object. =1/2xMxV². If the mass is in kilograms and the velocity is in meters/second, then the kinetic energy is in kilograms - meters squared/second.

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5 0

11 months ago

The diagram is a real world example of the first and second laws of thermodynamics. It shows how thermal energy is used to gener

Dmitriy789 [7]

Answer:

First law: kinetic energy is used to turn an electric generator

Second law: some thermal energy is lost to the environment as it travels through the system

Explanation:

The first law of thermodynamics is known as the law of conservation of energy. It states that energy can neither be created nor destroyed but can only be transferred or changed from one form to another. When thermal energy is used to generate electricity, the kinetic energy of the steam is used to turn the electric generator (thereby producing electrical energy).

The second law of thermodynamics states that energy transfer or transformation leads to an increase in entropy resulting in the loss of energy. This law also states that as energy is transferred or transformed, some is lost in a form that is unusable. When thermal energy is used to generate electricity, some of the thermal energy is lost to the environment as it travels through the system.

7 0

3 years ago

Read 2 more answers

Why does a magnet attract a steel nail

SVEN [57.7K]

Answer:

The nail will stick to the bar magnet because it will become magnetized, and it's metal. The presence of the nearby north pole rearranges the magnetic domains inside the steel so that their south poles all point toward the north pole of the permanent magnet. As a result, the other end of the nail becomes a north pole.Magnets attract iron due to the influence of their magnetic field upon the iron. ... When exposed to the magnetic field, the atoms begin to align their electrons with the flow of the magnetic field, which makes the iron magnetized as well. This, in turn, creates an attraction between the two magnetized objects.

7 0

3 years ago

Two particles with oppositely signed charges nC are placed at two of the vertices of an equilateral triangle with side length 3

babymother [125]

The magnitude of the electric field at the third vertex of the triangle is determined as zero.

<h3>Electric field at the third vertex of the triangle </h3>

The electric field at the third vertex of the equilateral triangle due to the other charges placed on the first and second vertices is calculated as follows;

E = E(13) + E(23)

E = (kq₁)/r² + (kq₂)/r²

where;

q1 is positive charge
q2 is negative charge

E = (kq₁)/r² - (kq₂)/r²

E = 0

Thus, the magnitude of the electric field at the third vertex of the triangle is determined as zero.

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5 0

2 years ago