this is for physics, i need help fast!!

Answer:

A. Heat flowing from cold to hot

Explanation:

The second law of thermodynamics speaks about entropy and directions of processes. These directions go only in one direction, just as time moves only in one direction, as we know it. It is impossible to see time moving forward in a different sense. In the same way, the processes associated with heat transfer, go in a single direction this direction is associated with bodies at different temperatures. Where heat is transferred from a higher temperature body to a lower temperature body.

Heat transfer processes from a cold body to a hot body, do not exist and can not be achieved in a natural way.

Answer:

C

Explanation:

Answer:

251.5 x 10⁻⁴ N  

Explanation:

Pressure = Force / surface area

Force = pressure x area

pressure = 118 mm of Hg

= .118 x 13.6 x 9.8 N / m²

= 15.72 N / m ²

area = 16 x 10⁻⁴ m²

Force = 15.72 x 16 x 10⁻⁴

= 251.5 x 10⁻⁴ N  .

Answer:

When you have a cloudy night, the clouds prevent heat from escaping through the atmosphere and into space.

The clouds act like a blanket and trap the heat it, and that is why every time you have a cloudy night, it is always warmer than a clear night.

Answer:

.

Explanation:

Given :

One particle, of mass m , moves with a speed v in the x-direction, and another particle, of mass 2 m , moves with a speed v/2 in the y-direction.

To Find :

The velocity of the center of mass of these two particles.

Solution :

Speed of mass m, [tex]v\ \hat i[/tex].

Speed of mass 2m , [tex]\dfrac{v}{2}\ \hat{j}[/tex] .

Speed of center of mass is given by :

[tex]v_{cm }= \dfrac{m\times( v\ \hat{i}) + 2m \times \dfrac{v}{2}\ \hat{j} }{m + 2m}\\\\v_{cm}=\dfrac{v( \hat{i} + \hat{j})}{3}[/tex]

Hence, this is the required solution.

The velocity of the center of mass of these two particles will be [tex]\rm v_{cm}= \frac{v(\vec i+\vec j)}{3}[/tex]

The change of displacement with regards to time is defined as speed. Speed is a scalar quantity. It is a time-based component. Its unit is m/sec.

The given data in the problem is

[tex]\rm V_i[/tex] is the speed of mass m

[tex]\rm \frac{v}{2} \hat j[/tex] is the speed of mass 2m

Speed of the center of mass will be;

[tex]\rm v_{cm}=\frac{m \times (v \hat i)+2m \times \frac{v}{2}\hat j }{m+2m} \\\\ \rm v_{cm}= \frac{v(\vec i+\vec j)}{3}[/tex]

Hence the  velocity of the center of mass of these two particles will be [tex]\rm v_{cm}= \frac{v(\vec i+\vec j)}{3}[/tex].

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Answer:

pic

Explanation:

The graph which best shows the velocity v of the quarter from when it is tossed up until it reaches the ground is attached in the answer.

Velocity is the time rate of change of displacement. The displacement and velocity both are vector quantities. They represent magnitude and direction as well.

A quarter is tossed up from the roof of a skyscraper and hits the sidewalk below.

The velocity will decrease with the time linearly.

The graph which best shows the velocity v of the quarter from when it is tossed up until it reaches the ground is attached in the solution.

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Answer:

[tex]v_{B} = \frac{m_{A}v_{A}}{m_{B}}[/tex]

Explanation:

We can apply the law of conservation of momentum on the nucleus in its initial and final state of nucleus:

Initial Momentum = Final Momentum

momentum of nucleus before bursting = momentum of piece A + momentum of Piece B

[tex](m_{nucleus})(velocity of nucleus) = m_{A}v_{A} + m_{B}v_{B}\\[/tex]

since, nucleus was initially at rest. Therefore,

velocity of nucleus = 0 m/s

and due to opposite direction of forces:

Vb = - Vb

Therefore,

[tex](m_{nucleus})(0) = m_{A}v_{A} - m_{B}v_{B}\\\\m_{A}v_{A} = m_{B}v_{B}\\\\v_{B} = \frac{m_{A}v_{A}}{m_{B}}[/tex]

Answer:

Pic not clear.........

Answer:

that gases are gases

Explanation:

Answer:

A. Some, but not all gases are harmful to humans.

Explanation:

Answer:

In real measurements, the acceleration that is measured is always less than the acceleration of gravity, therefore there must be a force that opposes the movement, which is why Aristotle says that vacuum stenos

Explanation:

When a rock starts the vacuum, there are no friction forces that make its movement, therefore, if close to the Earth, the rock has an acceleration equal to the acceleration of gravity.

In real measurements, the acceleration that is measured is always less than the acceleration of gravity, therefore there must be a force that opposes the movement, which is why Aristotle says that vacuum stenos

Answer:

0 m/s.

Explanation:

The average velocity from 3 to 4 seconds is 0 m/s.

Answer: i don’t know the answer but

Explanation:

Divide the distance by the speed. That gives the travel time.

t = d/v = (4200 km) / (800 km/hr) = ? hrs

Answer:

$ 29.16

Explanation:

The following data were obtained from the question:

Current (I) = 4.5 A

Voltage (V) = 120 V

Time (t) = 30 days

1 KWh = $ 0.15

Cost for 30 days =.?

From the question given above, we were told that the refrigerator runs 50% of the time.

Thus, the time of operation of the refrigerator will be:

Time (t) = 30 × 50% = 30 × 50/100

= 15 days.

Next, we shall convert 15 days to hours. This can be obtained as follow:

1 day = 24 h

15 days = 15 days × 24 h / 1 day

15 days = 360 h

Next, we shall determine the energy consumed in KWh This can be obtained as follow:

Current (I) = 4.5 A

Voltage (V) = 120 V

Time (t) = 360 h

Energy (E) =?

E = ivt

E = 4.5 × 120 × 360

E = 194400 Wh

Next, we shall convert 194400 Wh to KWh. This can be obtained as follow:

1000 Wh = 1 KWh

Therefore,

194400 Wh = 194400 Wh × 1 KWh/ 1000 Wh

194400 Wh = 194.4 KWh

Thus the energy consumed is 194.4 KWh

Finally, we shall determine the cost of energy consumed. This can be obtained as follow:

From the question given above,

1 KWh cost $ 0.15

Therefore, 194.4 KWh will cost = 194.4 KWh × $ 0.15 = $ 29.16

Therefore, the cost of running the refrigerator for 30 days is $ 29.16

Answer:

8.193x10^-21m/s²

Explanation:

We have it that the gravitational force that is acting on this object is equal to the earth's gravitational force.

We start by using this formula

Ma = mg

We make a the subject of formula

a = mg/M

m = 5000kg

g = 9.8

M = 5.98x10^24kg

mg = 5000x9.8

= 49000

49000/5.98x10^24

= 8.193x10^-21m/s²

The magnitude of the earth's acceleration is 8.20 × 10^27

The parameters given in the question are;

mass= 5000 kg

g= 9.81

earth's mass= 5.98 × 10∧ 24

The formula is

= mass × acceleration due to gravity/earth's mass

= 5000 × 9.81/ 5.98^24

= 49,050/5.98 × 10^24

= 8.20 × 10^27

Hence the magnitude of the earth's acceleration just before impact is 8.20 × 10^27

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Answer:

#_foton2 = 2.96 10¹⁶ photon / s

Explanation:

We are going to solve this exercise in parts, first we will calculate how many photons are in the beam and then the amount that pass through the pinhole.

To find the energy of a photon, let's use the Planck relationship

          E = h f

          c = λ f

we substitute

          E₀ = h c /λ

          E₀ = 6.63 10⁻³⁴ 3 10⁸/337 10⁻⁹

          E₀ = 5.90 10⁻¹⁹ J

Now we can use a direct ratio rule to find out the number of photons in the beam. If 1 photon has an energy E₀, how many photons are in an energy 5.00W

         # _foton = 1  5/ E₀ = 1 5 / 5.90 10⁻¹⁹

         #_foton = 8.5 10¹⁸ photons / s

This number of photons is uniformly distributed in the area of ​​the circle with diameter 5.90mm = 5.90 10⁻³m

      R= d/2=  2.95 10⁻³ m

     r = d/2 = 0.55 10⁻³ m

let's find the beam area

         A = π R²

         A = π (2.95 10⁻³)²

         A = 2.73 10⁻⁵ m²

the pinhole area

        a = π r²

        a = π (0.55 10⁻³)²

        a = 9.50 10⁻⁷ m²

Let's use another direct ratio (rule of three) if there are 8.5 1018 photons / s in an area A how many photons pass through the area at

         # _foton2 = 8.5 10¹⁸ a / A

         # _fotn2 = 8.5 10¹⁸ 9.50 10⁻⁷ /2.73 10⁻⁵

         #_foton2 = 2.96 10¹⁶ photon / s

Answer:

208.08 pounds

Explanation:

Given that,

Mass of a man, m = 75.5 kg

Starting from rest, the elevator ascends, attaining its maximum speed of 1.65 m/s in 0.675 s.

We need to find the value of spring scale during these 0.675 s.

As the elevator ascends, net force will be given by :

F = mg + ma

a can be calculated as follows :

[tex]a=\dfrac{1.65-0}{0.675}\\\\a=2.45\ m/s^2[/tex]

So,

F = 75.5[(9.81) + (2.45)]

F = 925.63  N

We know that,

1 N = 0.224 Pounds

It means, 925.63  N = 208.08 pounds

So, the spring scale will register 208.08 pounds.

Answer:

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

force = mass × acceleration

From the question we have

force = 32 × 0.5

We have the final answer as

Hope this helps you

Answer:

False

Explanation:

Im pretty sure the answer is false

Answer:

the relative age of lower layers of rock is more than the relative age of rocks above them.

Answer:

Key components of games are goals, rules, challenge, and interaction.

Explanation:

Hope I helped.

Answer:

the name of the games are goals, rules, challenges and interaction and mabe there can be more.

Explanation:

I hope this helped your day better this is the correct answer i got it correct on the test.

Answer:

dB / dt = -141.47 T / s

Explanation:

For this exercise let's use Faraday's law to calculate the induced electromotive force

          E = - N dФ / dt

the magnetic flux is

         Ф = B. A

in this case the direction of the field and the normal to area are parallel so the scalar product is reduced to the algebraic product

         Ф = B A

  we substitute

        E = - N A dB / dt

the area of ​​the loop is

        A = π r²

we substitute

          E = - N π r² dB / dt

in the exercise indicate that the resistance of the coil is R = 50.0 Ω,

           E = i R

we substitute

           i R = -N π r² dB / dt

           dB / dT = - i R / N π r²

let's calculate

           dB / dt = - 5.00 50.0 / (100 π 0.075²)

           dB / dt = -141.47 T / s

Answer:

f

Explanation:

Answer:

yeah but if you get in your 30s you start to lose muscles

Answer:

protons and electrons

Answer:

i am in the southern hemisphere

Explanation:

Answer:

its winter ................

Answer:

50m

Explanation:

Given parameters:

Initial velocity  = 20m/s

Acceleration  = 4m/s²

Time  = 10s

Unknown:

Distance traveled by the rocket  = ?

Solution:

To solve this problem use the expression below;

     v² = u² + 2as

v is the final velocity

u is the initial velocity

a is the acceleration

s is the distance

  final velocity = 0

 Insert the parameters and solve;

  0²  = 20² + 2 x 4 x s

   -400  = 8s

         s  = 50m

   Disregard the negative sign because distance cannot be negative.

Answer:

 T = 556K

Explanation:

For this exercise let's use Stefan's law

        P = σ A e T⁴

where the stafan-Boltzmann constant is 5,670 10⁻⁸ W / m² K⁴.

In this case the area of ​​a circular cylinder is

        A = π r²

the radius is

         r = d / 2 = 0.150 m

        A = π (0,150)²

        A = 7.0685 10⁻² m²

let's clear

         T⁴ = P /σ A e

         T⁴ = 100 / (5.670 10⁻⁸   7.0685 10⁻²  0.26)

         T⁴ = 9.5966 10¹⁰ = 959.66 10⁸

         T = 5.56 102 K

         T = 556K

The temperature of the filament is 366.3 K

Using the equation for radiated power, P

P = σεAT⁴ where σ = Stefan-Boltzmann constant = 5.67 × 10⁻⁸ W/m²K⁴, ε = emissivity = 0.26, A = area of cylindrical tungsten filament = πDh (since it radiates through its sides)where D = diameter of tungsten filament = 0.40 mm = 0.4 × 10⁻³ m and h = length of tungsten filament = 30.0 cm = 0.3 m and T = temperature of tungsten filament.

Since we require the temperature of the filament, making T subject of the formula, we have

T = ⁴√(P/σεA)

T = ⁴√(P/σεπDh)

Since P = 100 W, substituting the values of the variables into the equation, we have

T = ⁴√(P/σεπDh)

T = ⁴√(100 W/5.67 × 10⁻⁸ W/m²K⁴× 0.26 × π× 0.4 × 10⁻³ m × 0.3 m)

T = ⁴√(100 W/0.5558 W/K⁴ × 10⁻⁸)

T = ⁴√179.93 × 10⁸ K⁴)

T = 3.663 × 10² K

T = 366.3 K

So, the temperature of the filament is 366.3 K

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Answer:

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Explanation:

Answer:

A)

Explanation:

This is because the longer the wire is, the more resistance there is for the electricity to run through.

The student can increase the resistance by replacing the wire with one that is longer. Thus, option A is correct.

The voltage across a conductor, according to Ohm's law, is precisely proportional to the current that passes through it.

A wire's resistance is inversely correlated with its cross-sectional area and directly correlated with its length. Most conductors have a resistance to the flow of an electric current through them. As the wire's length increases, the resistance in the wire rises.

However, according to Ohms law V=IR, a wire's length increases its resistance while decreasing its current for a given potential difference (voltage).

Therefore, replacing the wire with a longer one will increase resistance if a student plans to modify a circuit.

Thus, option A is correct.

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Answer:

a. a black hole

Explanation:

X-ray emission from the central degrees of the Milky Way Bright X-ray emission traces the coherent edge brightened shell-like feature, dubbed the northern chimney, located north of Sgr A* and characterized by a diameter of about 160 pc. On the opposite side, the southern chimney appears as a bright linear feature. Bright X-ray emission is observed at high latitude