A decorative plastic film on a copper sphere of 10 mm diameter in an oven at 750C. Upon removal from the oven, the sphere is subjected to an air stream at 1 atm. , and 230C having a velocity of 10 meter/sec. Estimate how long it will take to coal the sphere to 350C? Density of copper is 8933 kg/m3 , thermal conductivity k = 399 W/m.K and specific heat Cp = 387 J/kg.K. for Air at an average temperature of T[infinity] = 296 K has viscosity µ= 181x10-7 N.s/m2 , kinematic viscosity ν = 15.36x10-6 m2/s and thermal conductivity k = 0.0258 W/m.K and Prandtl No. Pr = 0.709 and air at surface temperature Ts = 328 K will have viscosity µs = 197x10-7 N.s/m2

Answer:

Be serious or else CEO of brainly will kick you out

Answer:

difference between mass and weight is that mass is amount of matter in a material while weight is a measure of how the force of gravity acts upon that mass.the mass of an object will be same on earth and mars but its weight on both planets will be different.

Answer:

The gravitational force between m₁ and m₂, is approximately 1.06789 × 10⁻⁶ N

Explanation:

The details of the given masses having gravitational attractive force between them are;

m₁ = 20 kg, r₁ = 10 cm = 0.1 m, m₂ = 50 kg, and r₂ = 15 cm = 0.15 m

The gravitational force between m₁ and m₂ is given by Newton's Law of gravitation as follows;

[tex]F =G \cdot \dfrac{m_{1} \cdot m_{2}}{r^{2}}[/tex]

Where;

F = The gravitational force between m₁ and m₂

G = The universal gravitational constant = 6.67430 × 10⁻¹¹ N·m²/kg²

r₂ = 0.1 m + 0.15 m = 0.25 m

Therefore, we have;

[tex]F = 6.67430 \times 10^{-11} \ N \cdot m^2/kg \times \dfrac{20 \ kg\times 50 \ kg}{(0.1 \ m+ 0.15 \ m)^{2}} \approx 1.06789 \times 10^{-6} \ N[/tex]

The gravitational force between m₁ and m₂, F ≈ 1.06789 × 10⁻⁶ N

Answer:

a) ii

b) i

c)iii

d)iii

e) i

f)iii

Explanation:

i hope this will help

Answer:

the answer of b is N and d is mol

Answer:

A. Contains DNA

C. Contains ribosomes

F. Lacks a nucleus

Explanation:

The small ball will transfer its momentum to the heavier ball. Since the momentum gets conserved. The velocity will depend upon the mass of the balls.

According to the law of conservation of momentum. The momentum of the body before the collision is always equal to the momentum of the body after the collision.

The momentum of the body is given by the product of the mass and velocity of the body.

According to the law of conservation of momentum

Momentum before collision =Momentum after collision

Hence the small ball will transfer its momentum to the heavier ball.

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Answer:

Distancia, D = 170,000 metros

Explanation:

Dados los siguientes datos;

Para encontrar la distancia recorrida, en metros;

Matemáticamente, la distancia recorrida por un objeto se calcula mediante la fórmula;

Distancia = velocidad * tiempo

Sustituyendo los valores en la fórmula, tenemos;

Distancia = 85 * 2

Distancia = 170 kilómetros

A continuación, convertiríamos el valor en kilómetros a metros;

Conversión:

1 kilómetros = 1000 metros

170 kilómetros = D metros

Multiplicación cruzada, tenemos;

D = 170 * 1000

D = 170,000 metros

Por lo tanto, habría viajado 170,000 metros después de 2 horas.

Answer:

Solition given:

focal length(f)=20cm

size of image(v)=2x

size of object(u)=x

we have

power of lens= reciprocal to focal length=1/20=0.05/cm

ii.

the position of the image is beyond C.

Explanation:

See the attachment !!!!!!!

Answer:

9.26 km/h

Explanation:

Applying,

V' = D'/t'............... Equation 1

Where V' = Average speed, D' = Total distance, t' = total time.

Given: D' = 5 km

But,

v = d/t............ Equation 2

Where v = speed , d = distance, t = time

t = d/v............ Equation 3

Given: d = 4.5 km, v = 9 km/h, and d = 0.5 km, v = 12.5 km/h

Therefore,

t₁ = 4.5/9 = 0.5 hours

t₂ = 0.5/12.5

t₂ = 0.04 hours

Therefore,

V' = 5/(0.5+0.04)

V' = 5/0.54

V' = 9.26 km/h

Gamma rays

used in radiotherapy

Answer:

1.for the first one 100centimeters make 1 meter therefore

100cm-1m

340cm-x

340/100

=3.4

the answer is supposed to be 3.4, maybe there's a mistake with the question or the answer

2.the weight of a body is given by the formula

mass×gravity,in this case the mass is 75kg and the gravity is 9.8

weight=75×9.8

=735N

3.for this one the mass of a body is given by the formula

mass=weight/gravity

=420/9.8

=42.8kg

I hope this helps

The total cost of the energy consumption for the given time period is $0.0364

The given parameters include;

The total energy consumed in the process of heating the water;

Total electrical Energy  = Energy of the heater (kWh) + Energy of the heated water (kWh)

Energy of the heater (kWh) = power x time

                                = 4 kW x 0.067 h

                                 = 0.268 kWh

Energy of the heated water (J) = mcΔt

where;

Δt is the change in temperature = t₂ - t₁

                                                      = 50 ⁰C  -  20 ⁰C = 30⁰C

Energy of the heated water (J) = 1 x 4200 x 30

                                               = 126,000 J

Electrical power of the heated water (Watts) = [tex]\frac{126,000 \ J}{4 \ \min} \times \frac{1 \min}{60 \ s} = 525 \ W[/tex]

Energy of the heated water (kWh) = [tex]\frac{525}{1000} \times 4\min\times \frac{1 \ hr}{60 \min} = 0.035 \ kWh[/tex]

Total electrical Energy  = 0.268 kWh  +  0.035 kWh

                                       = 0.303 kWh

The total cost of the energy consumed is calculated as;

[tex]Total \ cost = \frac{\$ \ 0.12}{kWh} \times 0.303 \ kWh = \$ \ 0.0364[/tex]

Therefore, the total cost of the energy consumption is $0.0364

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Answer:

θ = 66º

Explanation:

This exercise of Newton's second law must be solved in part, let's start by finding the slowing down acceleration of the ball

           a = v² / r

the radius of the circle is

          sin θ = r / L

          r = L sin θ

we substitute

          a = v² /L sin θ

now let's write Newton's second law

vertical axis

            T_y -W = 0

             T_y = W

radial axis

            Tₓ = m a                 (1)

let's use trigonometry for the components of the string tension

             cos θ = T_y / T

             sin θ = Tₓ / T

             Tₓ = T sin θ

we substitute in 1

            T sin θ = [tex]\frac{m \ v^2}{L \ sin \theta}[/tex]

             T L sin² θ = m v²

we write our system of equations

             T cos θ  = m g

             T L sin ² tea = m v²

we divide the two equations

             L [tex]\frac{sin^2 \theta}{cos \theta}[/tex] = v² / g

             (1 -cos²)/ cos θ  = [tex]\frac{v^2 }{g \ L}[/tex]

             1 - cos² θ  =  [tex]\frac{4.75^2}{9.81 \ 2.37}[/tex]   cos θ

             cos² θ + 0.97044 cos θ -1   = 0

we change variable    cos  θ = x

             x² + 0.97044 x - 1 =0

             x= [tex]\frac{-0.97 \pm \sqrt{0.97^2 - 4 1} }{2}[/tex]

           since the square root is imaginary there is no real solution to the problem, suppose that the radius is 1 m r = 1 m

           T sin θ = [tex]\frac{m \ v^2}{ r}[/tex]

           T cos θ  = m g

resolved

           tan θ =  [tex]\frac{v^2}{ r g}[/tex]

           θ = tan⁻¹ ( 4.75²/ 1 9.81)

           θ = 66º

Answer:

Explanation:

Vernier scale

Mathematical tool

A vernier scale, named after Pierre Vernier, is a visual aid to take an accurate measurement reading between two graduation markings on a linear scale by using mechanical interpolation; thereby increasing resolution and reducing measurement uncertainty by using vernier acuity to reduce human estimation error. Wikipedia

Purpose: Measuring more precisely than could be done unaided when reading a uniformly divided straight or circular measurement scale

Creator: Pierre Vernier

Year invented: 1631

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

A micrometer is a measuring instrument that can make extraordinarily precise measurements. Most micrometers are designed to measure within one one-thousandth of an inch! That's a close fit. Exact measurements like this are necessary when even the smallest of space between objects can cause problems or difficulties.

Micrometer

Mathematical tool

A micrometer, sometimes known as a micrometer screw gauge, is a device incorporating a calibrated screw widely used for accurate measurement of components in mechanical engineering and machining as well as most mechanical trades, along with other metrological instruments such as dial, vernier, and digital calipers. Wikipedia

Operation supported: Component measurement

Purpose: Precision measurement of a component

Variant: Digital mics, Bench micrometer, Limit mics, Digit mics, MORE

Component: Screw, Spindle, Ratchet stop, Anvil, Frame, Barrel, Thimble lock, Thimble

Application: Mechanical Engineering, Machining

Answer:

enjoy

Explanation:

The number of time a cricket chirps in a minute is a function of the temperature in the formula: n=4t-160, where n=number of times a cricket chirps a minute and t=temperature in farenheit. You can use the temperature t=(1/4)n+40 to estimate the temperature based on the number of chirps per minute.

Answer:

Acceleration is the rate of change of velocity with time.its system international unit is meters per second square.

I hope this helps

Explanation:

string roller is called an example of wheel and axel because The thin rod which needs to be turned is called the axle and the wider object fixed to the axle, on which we apply force is called the wheel.

hence the we apply force on the roller and the string gets tight.

Answer:

Kepler's laws apply: First Law: Planetary orbits are elliptical with the sun at a focus. Second Law: The radius vector from the sun to a planet sweeps equal areas in equal times. Third Law: The ratio of the square of the period of revolution and the cube of the ellipse semimajor axis is the same for all planets.

Answer:

C.  Current.

Explanation:

In a series circuit the current is equal in all of its components, so to measure the current we put the meter in series with the circuit.

Total distance = 10 km + 10 km = 20 km

1 km = 1000 m

20km x 1000 = 20,000 m

Total time = 20 min. + 30 min. = 50 minutes

Average speed = Distance /  time

Average speed = 20,000/50 min

Average speed = 400 m/s

Answer:

v = 2.85 m/s

Explanation:

Given that,

A skipper on a boat notices wave crests passing his anchor chain every 5.6 s.

The distance between wave crests to be 16 m.

We need to find the speed of the waves. The speed of a wave can be calculated by the formula as follows :

[tex]v=f\lambda\\\\v=\dfrac{\lambda}{T}\\\\v=\dfrac{16}{5.6}\\\\v=2.85\ m/s[/tex]

So, the speed of the wave is 2.85 m/s.

Answer:

tôi đoán lagf  pjhAWN ỨNG HÓA HỌC

Explanation:

We know

[tex]\boxed{\sf W=Fscos\theta}[/tex]

[tex]\\ \sf\longmapsto W=25(20)cos30°[/tex]

[tex]\\ \sf\longmapsto W=500\times \dfrac{\sqrt{3}}{2}[/tex]

[tex]\\ \sf\longmapsto W=250\sqrt{3}[/tex]

[tex]\\ \sf\longmapsto W=250(1.73)[/tex]

[tex]\\ \sf\longmapsto W\approx 430J[/tex]

Option a) 430 J work done he do after walking 20.0 m.

Work, in physics, is a measure of energy transfer that happens when an object exists moved over a distance by an external force at least part of which exists involved in the direction of the displacement.

Displacement exists as the distance moved in a straight line, in a provided direction, from the starting point. Displacement exists as a vector quantity as it includes size and direction.

An angle stands the figure formed by two rays, named the sides of the angle, sharing a standard endpoint, named the vertex of the angle.

⇒[tex]W=Fcos\theta[/tex]

⇒[tex]W=25(20)cos 30^{0}[/tex]

Then,

⇒[tex]W=50*\sqrt{3} /2[/tex]

⇒[tex]W=250\sqrt{3}[/tex]

Hence,

⇒[tex]W=250(1.73)[/tex]

[tex]W[/tex] approximately 430J.

Hence, Option a) 430 J work done he do after walking 20.0 m.

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Answer:

The answer is below

Explanation:

Una partícula efectúa un MAS cuya ecuación es: x=0.3cos (2t + π/6) m. Determinar: Amplitud, frecuencia angular, fase inicial, periodo, frecuencia de oscilación y posición en t=0.25 s

Solution:

La ecuación de la onda es:

x = A cos (ω t + Ф), donde:

A = amplitud, ω = frecuencia angular = 2 π / T = 2 π f, Ф = fase inicial, f = frecuencia, T = período

Por lo tanto, comparando la ecuación de la onda con x = 0.3cos (2t + π / 6), obtenemos:

a) A = 0.3

b) ω = 2 rad / s

c) Ф = π / 6 rad

d) ω = 2π / T

2 = 2π / T

T = 3.14 s

e) ω = 2πf

2 = 2πf

f = 0.32 Hz

f) en t = 0.25 s:

x (t) = 0.3cos (2 * 0.25 + π / 6) = 0.22 m

Answer:

contains many individual light detectors, each with its own lens

Explanation:

The compound eye is found mainly in insects and crustaceans, it is composed of individual receptor units, each with its focus, sensing nerve; each one gives a small image of the environment, so the image is mosaic type, not a complete integral image of the environment.

When reviewing the different statements, the correct one is

contains many individual light detectors, each with its own lens

Answer:

The force is 3305.6 N.

Explanation:

Final velocity, v = 0

time, t = 2.25 ms

initial velocity, u = 4.25 m/s

mass, m = 1.75 kg

Let the acceleration is a.

Use first equation of motion.

v = u + a t

0 = 4.25 + a x 0.00225

a = - 1888.9 m/s^2

The force is

F = ma

F = 1.75 x 1888.9

F = 3305.6 N

Answer:

The principle of conservation of energy states that in a closed system, the energy can neither be created nor destroyed between interacting particles and remains constant or transformed from one form to another

In the jet engine, the release of jet changes the number of interacting particles in the engine, and given that energy cannot be created in the instantaneously closed system of the engine, energy is carried away and therefore lost by particles in the jet exhaust

The conservation of energy principle is therefore obeyed in the condition in which the jet engine losses energy by the release of jet

Explanation:

Answer:

A ball rolls off the table and free falls to the ground. Which statement accurately describes its acceleration? Its acceleration is downward but remains a constant value as it falls.