A mass M subway train initially traveling at speed v slows to a stop in a station and then stays there long enough for its brakes to cool. The station's volume is V and the air in the station has a density rho_air and specific heat C_air.
Assuming all the work done by the brakes in stopping the train is transferred as heat uniformly to all the air in the station, what is the expression for the change in the air temperature in the station? Make sure the quantities you enter match the ones given in the problem exactly.

Answer:

Explanation:

the 40-watt bulb is going to require less energy to power.

Answer:

960 N

Explanation:

answer should have two signif digits  

a = change in velocity divided by change in time

   1 m/s / .5 s =   2 m/s^2

F = ma      a = g + 2 m/s^2 = 9.81 + 2 =  11.81 m/s^2

  81 kg * 11.81 m/s^2   = 956.61   N = ~ 960 N  (two sig digits)

(Please let me know if this is incorrect....I am not SURE )

Answer:

the required speed with which the missile move relative to the Earth is -0.727c

Explanation:

Given the data in the question;

relative velocity relation;

u' = u-v / 1 - \(\frac{uv}{c^2}\)

so let V\(_B\) represent the velocity as seen by an external reference frame; u=V\(_B\)

and let V\(_A\) represent the speed of the secondary reference frame; v=V\(_A\)

hence, u' is the speed of B as seen by A

so

u' = V\(_B\)-V\(_A\) / 1 - \(\frac{V_BV_A}{c^2}\)

now, given that; V\(_A\) = 0.9c  and V\(_B\)  = 0.5c

we substitute

u' = ( 0.5c - 0.9c ) / 1 - \(\frac{(0.5c)(0.9c)}{c^2}\)

u' = ( 0.5c - 0.9c ) / 1 - \(\frac{c^2(0.5)(0.9)}{c^2}\)

u' = ( 0.5c - 0.9c ) / 1 - (0.5 × 0.9)

u' = ( -0.4c ) / 1 - 0.45

u' = -0.4c / 0.55

u' = -0.727c

Therefore, the required speed with which the missile move relative to the Earth is -0.727c

Answer:

The magnitude of the friction force is 8197.60 N

Explanation:

Using the definition of the centripetal force we have:

\(\Sigma F=ma_{c}=m\frac{v^{2}}{R}\)

Where:

Now, the force acting in the motion is just the friction force, so we have:

\(F_{f}=m\frac{v^{2}}{R}\)

\(F_{f}=2100\frac{18^{2}}{83}\)

\(F_{f}=8197.60 \: N\)

Therefore the magnitude of the friction force is 8197.60 N

I hope it helps you!

Taking half of the given length and pulling it to a length of 2L as before, the frequency obtained by vibrating in the basic method is 6fo. option(ii)

When a bow vibrates in its fundamental mode with a length of 2L, the frequency is denoted as f. Now, let's consider the scenario where half of the given length (L) is pulled to a length of 2L.

In the fundamental mode of vibration, the frequency is inversely proportional to the length of the vibrating object. Therefore, if the length of the bow is halved to L, the frequency would double to 2f.

When this new length of L is pulled to a length of 2L, we need to determine the frequency obtained in the fundamental mode.

Since the frequency is inversely proportional to the length, we can use the inverse relationship to find the new frequency.

If the original frequency was 2f at length 2L, when the length is reduced to L, the new frequency would be (2f)/(2L) = f/L.

Now, if this length of L is stretched to 2L again, the new frequency in the fundamental mode would be (f/L) * (2L) = 2f. option(ii)

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Answer:

6.25

....................

Explanation:

100/16 = 6.25

The primary locations for the birth of new stars are in galaxies' spiral arms. The proportion of the galaxy that can participate in star formation increases as more gas and dust become available.

We refer to some spiral galaxies as "barred spirals" because the centre bulge seems extended, like a bar. The spiral arms of the galaxy seem to emerge from the ends of the bar in barred spirals. Elliptical galaxies are round or oval in shape, as their name implies, and have a rather uniform distribution of stars.

The Norma and Cygnus arm, Sagittarius, Scutum-Crux, and Perseus arms are the four principal spiral arms of the Milky Way.

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First, find the time that it takes for the sparrow to travel 0.500m at a speed of 1.80 m/s. Since speed is the ratio between distance and the time taken to travel that distance, then:

Isolate t from the equation:

Replace d=0.500m and v=1.80 m/s to find the time:

During that time, the sparrow falls vertically according to the equation:

Where g is the gravitational acceleration on Earth:

Replace the value of g and t=0.2777...s to find how far does the sparrow fall:

If the initial speed is increased, it will take less time to travel 0.500m, and then, the falling time will be decreased, and so the distance of fall would decrease. However, the horizontal speed does not affect the distance of fall if the fall time is the same (but the horizontal displacement would increase).

Therefore, the answers are:

a) The sparrow falls a distance of 0.378m

b) The distance of fall would decrease since it would take less time to travel 0.500m.

At the given erro in angle, the error in the measurement of sin 90 degrees would be 0.001.

The percentage error of any measurement is obtained from the ratio of the error to the actual measurement.

The error of sin 90 degrees is calculated as follows;

sin 90 = 1

error in measurement = sin(90 - 0.5)

error in measurement = sin(89.5) = 0.999

Error in sin 90 degrees = 1 - 0.999

Error in sin 90 degrees = 0.001

Thus, at the given erro in angle, the error in sin 90 degrees would be 0.001.

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Answer:

I would say d I had the same question yesterday and I got it correct so hope that helps

Answer:

another. persist. continue. last. remain.

Explanation:

The kinetic energy of the book after it is slids a distance of 2 meters will be 10 Joules.

The work-energy theorem states that "the work done on an object is the change in its kinetic energy".

Hence;

Kinetic energy = work done

Note that: work-done is expressed as:

Work done = f × d

Where f is force applied and d is distance traveled.

Given that:

Force applied f = 5 newton

Distance d = 2 meters

Work done = ?

Plug these values into the above formula and solve for the workdone.

Work done = f × d

Work done = 5N × 2m

Work done = 10Nm

Work done = 10 Joules

Therefore, the kinetic energy is 10 Joules.

Option B) 10 J is the correct answer.

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Kinetic energy is gotten from wind which is converted into rotational energy.

The wind is used to produce electricity using the kinetic energy created by air in motion wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical ability can be used for particular tasks (such as grinding grain or forcing water) or can be converted into electricity by a generator. into electricity. In present wind turbines, wind rotates the rotor blades, which change kinetic energy into rotational energy. Wind turbines labor on an easy principle: in lieu of using electricity to make wind like a fan wind turbines use the wind to make electricity. The wind turns the rotter-like blades of a turbine around a rotor, which spins a generator, which produced electricity.

So we can conclude that Wind rotates the rotor blades that convert kinetic energy into rotational energy.

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Answer:

6.93 × 10⁶ s

Explanation:

We know that the rate of gas leakage in the balloon is given by

dm/dt = -kCV where m = mass of gas, k = mass transfer coefficient = 1 × 10⁻⁷ cm/s, C = concentration of gas in balloon and V = volume of gas in balloon.

We know m = CV, so

dm/dt = dCV/dt = -kCV

CdV/dt = -kCV

dV/dt = -kV

Separating the variables, we have

dV/V = -kdt

Integrating both sides, we have

∫dV/V = -∫kdt

㏑V = -kt + C

V = exp(-kt)exp(C)

V = \(Ae^{-kt}\)

when t = 0, V = V₀

\(V_{0} = Ae^{-k0}\\V_{0} = Ae^{0}\\V_{0} = A\)

\(V = V_{0} e^{-kt}\)

Now since V₀ = 1000 cm³ and we require the time when V = 500 cm³.

Substituting V and V₀ into the equation, we have

\(500 = 1000 e^{-kt}\\500/1000 = e^{-kt}\\1/2 = e^{-kt}\)

taking natural logarithm of both sides, we have

㏑(1/2) = -kt

t = -㏑(1/2)/k

substituting the value of k we have

t = -㏑(1/2)/1 × 10⁻⁷ cm/s

t = 0.693 × 10⁷ s

t = 6.93 × 10⁶ s

.The power of the car is 12.8 watt or 0.017 hp.

Work done per unit time is power of a machine. It is a scalar quantity. Its S.I. unit is watt(w). Energy change is equal to power.

1 hp is equal to 746 w.

The given is,

mass of car = 1380 kg

Initial velocity V1 = 65km/s

Final velocity V2 = 80 km/s

Time t = 7 s

change in kinetic energy = 1/2m ( -v12 = 1/2 ×(80-65) J

                                                  =  1/2×180

                                                       = 90 J

This is equal to work done.

Now. power = W/t

90/7 = 12.8 w

So the power is 12.8 w = 12.8/ 746 w

                                      0.017 hp.

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Answer:

yes

Explanation:

the brain perform two separate tasks at the same time

The boxes acceleration up the ramp is approximately 0.109 m/s².

The forces acting on the box can be resolved into two components: one parallel to the incline (F_parallel) and one perpendicular to the incline (F_perpendicular).

Given:

Mass of the box (m) = 40.7 kg

Coefficient of kinetic friction (μ) = 0.17

The force pulling the box (F_p) = 173 N

Incline angle (θ₁) = 14.5°

Force angle (θ₂) = 25.7°

First, we need to calculate the components of the force pulling the box:

F_parallel = F_p * sin(θ₂)

F_perpendicular = F_p * cos(θ₂)

Next, let's calculate the force of friction:

F_friction = μ * (mass of the box) * g, where g is the acceleration due to gravity (approximately 9.8 m/s²)

The force component parallel to the incline is opposed by the force of friction, so:

Net force parallel to the incline (F_net_parallel) = F_parallel - F_friction

Now, we can calculate the acceleration using Newton's second law:

F_net_parallel = (mass of the box) * acceleration

Rearranging the equation, we get:

acceleration = F_net_parallel / (mass of the box)

Now we can substitute the values into the equations and calculate the acceleration

F_parallel = 173 N * sin(25.7°) ≈ 73.88 N

F_perpendicular = 173 N * cos(25.7°) ≈ 154.37 N

F_friction = 0.17 * (40.7 kg) * 9.8 m/s² ≈ 69.44 N

F_net_parallel = F_parallel - F_friction ≈ 73.88 N - 69.44 N ≈ 4.44 N

acceleration = (4.44 N) / (40.7 kg) ≈ 0.109 m/s²

Therefore, the box's acceleration up the ramp is approximately 0.109 m/s².

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Answer:

d your welcome ehhehe:)

The arrow pointing downward is gravitational force, F(g), The left arrow is the applied force, F(t), The right arrow is frictional force, F(f) and the arrow pointing upward is the net force, F(n).

A force is a push or pull upon an object resulting from the object's interaction with another object. Forces can cause an object to accelerate or change its direction of motion.

Forces can be described by their magnitude and direction. In physics, forces can be caused by many interactions, including gravity, electromagnetic forces, and the strong and weak nuclear forces.

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Answer:

no

gravitational force between them is far smaller than the frictional force between the guy and the bench

Answer:

ight bet

Explanation:

Answer:

Explanation:

When the elevator is accelerating downwards, the apparent weight of the person is reduced, and when the elevator is accelerating upwards, the apparent weight is increased.

First, we need to determine the actual weight of the person. We can do this by using the formula:

Weight = mass x gravity

where mass is the mass of the person and gravity is the acceleration due to gravity, which is approximately 9.81 m/s^2.

Weight = (598.900 N) / (9.81 m/s^2) = 61.048 kg

Now, when the elevator is not moving, the person is only experiencing the force due to gravity, which is:

Weight = mass x gravity = (61.048 kg) x (9.81 m/s^2) = 598.78 N

Therefore, the scale would read approximately 598.78 Newtons when the elevator is not moving.

The magnitude of the angular acceleration of the roller is approximately 108.8 rad/s².

To find the magnitude of the angular acceleration of the roller, we can use the rotational analog of Newton's second law: τ = Iα, where τ is the torque, I is the moment of inertia, and α is the angular acceleration.

First, let's calculate the moment of inertia of the roller. The moment of inertia of a solid cylinder rotating about its central axis is given by the formula: I = (1/2)mr², where m is the mass and r is the radius.

Given:

Mass of the roller (m) = 2.4 kg

Radius of the roller (r) = 3.8 cm = 0.038 m

Moment of inertia (I) = (1/2) * 2.4 kg * (0.038 m)² = 0.0021744 kg·m²

Next, we need to calculate the torque (τ) applied to the roller. Torque is given by the formula: τ = rFsin(θ), where r is the distance from the axis of rotation to the point of application of the force, F is the magnitude of the force, and θ is the angle between the force and the line connecting the axis of rotation and the point of application.

Given:

Force applied (F) = 16 N

Angle (θ) = 35°

Distance from the axis of rotation to the point of application (r) is equal to the radius of the roller, so r = 0.038 m.

Torque (τ) = (0.038 m) * (16 N) * sin(35°) = 0.2366 N·m

Now, we can use the equation τ = Iα and solve for the angular acceleration (α):

0.2366 N·m = (0.0021744 kg·m²) * α

α = 0.2366 N·m / 0.0021744 kg·m² ≈ 108.8 rad/s²

Therefore, the magnitude of the angular acceleration of the roller is approximately 108.8 rad/s².

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A set of coordinates on a map grid are called coordinate grid or grid squares.

The quadrants in which ordered pairings, or coordinates, are established typically have two or more intersecting lines. Coordinates are also used in maps.

Eastings and Northings, two types of grid lines, are what make up the grid squares you see on maps. Both Easting and Northing grid lines are numbered from west to east and from south to north, respectively. The vertical lines that separate the map's west and east halves are known as eastings.

GPS coordinates, which are frequently stated in alphanumeric characters, can be used to uniquely identify a specific geographic place on the planet. In this context, coordinates refer to the points where a grid system intersects. Typically, GPS coordinates are written as a combination of latitude and longitude.

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Answer:

C. The poster provides an emotional picture of a young, innocent girl with a slightly worried expression to make protective feelings.

Explanation:

The girl looks quite worried in the poster. Attached is the image:

Walrus' kinetic energy = 2.05 x \(10^6\) J.

To calculate the walrus' kinetic energy,

we need to use the formula KE = 0.5\(mv^2\), where m is the mass of the walrus and v is its velocity.

We know the mass of the walrus is 907 kg and its velocity is 23 m/s.

Substituting these values in the formula, we get KE = 0.5 x 907 x \((23)^2\) = 2.05 x\(10^6\) J.

Therefore, the walrus' kinetic energy is 2.05 x \(10^6\) J.

It is important to note that kinetic energy is the energy an object possesses due to its motion, and is directly proportional to both its mass and velocity.

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Answer:

27.2m approx

Explanation:

Given data

Work done= 4000J

mass= 15kg

W= mg

W= 15*9.81

W= 147.15N

We know that

Work done= W*d

substitute

4000=147.15*d

divide both sides  by 147.15

d= 4000/147.15

d=27.18

Hence the distance is 27.2m approx

Answer:

brown or black

Explanation:

becuase the colors will layer

Answer:

fem = 7.58 10⁻⁵ V

Explanation:

For this exercise we use Faraday's law

          fem =   \(- \frac{d \Phi _B}{dt}\)

the magnetic flux is

          Ф_B = B. A = B A cos θ

Tje bold are vectros.  Suppose the case where the normal to the surface of the red blood cell is parallel to the field, therefore the angle is zero and the cos 0 = 1

The red blood cell area is

          A =π r²

indicate that the diameter is r = 8.00 mm = 8.00 10⁻³ m

the magnetic field has a frequency of f=60 Hz, and B₀ = 1.00 10⁻³T,  therefore we can write it

          B = B₀ sin (wt) = B₀ sin( 2π f t)

we substitute

           fem = - A dB / dt

           fem = - A B₀  \(\frac{ d (sin ( 2\pi f t)}{dt}\)

           fem = - π r² Bo (2πf  cos 2πft)

the maximum electromotive force occurs when the function is ±1

           fem = 2 π² r² B₀ f

let's calculate

           fem = 2π²  (8.00 10⁻³)²  1.00 10⁻³ 60

           fem = 7.58 10⁻⁵ V