In which case would electrical potential energy be built up and stored in the electric field?

What is the main determining factor in defining boundaries between layers of earth's atmosphere?

konstantin123 [22]

The main determining factor in defining boundaries between layers of earth's atmosphere would be temperature changes in these layers. Temperature is one essential property that varies in the atmosphere. Based from this variation, the atmosphere is divided into four major layers and further to three smaller layers - troposphere, tropopause, the stratosphere, stratopause, the mesosphere, mesopause, and the thermosphere.The troposphere is the layer that is nearest to the surface of the Earth. It is the part where humans, plants and animals survive. Also, it is the warmest layer of the atmosphere. And as we go higher the atmosphere, the temperature would drop making it much cooler.

5 0

3 years ago

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Annealing is a process by which steel is reheated and then cooled to make it less brittle. Consider the reheat stage for a 100-m

Anit [1.1K]

Complete question is;

Annealing is a process by which steel is reheated and then cooled to make it less brittle. Consider the reheat stage for a 100 mm thick plate (ρ = 7830 kg/m³, Cp = 550 J/Kg.K, k = 48 W/m K). The plate initially is at 200 °C and is to be heated to a minimum temperature of 550 °C. Heating is effected in a gas-fired furnace where the products of combustion at T∞ = 800 °C maintain a convection heat transfer coefficient of h = 250 W/m.K on both surfaces of the plate. How long should the plate be left in the furnace?

Answer:

860 seconds

Explanation:

We are given;

Initial Temperature; T_i = 200 °C

Minimum Temperature; T_o = 550 °C

T∞ = 800 °C

convection coefficient; h = 250 W/m².K

ρ = 7830 kg/m³

Cp = 550 J/kg K

k = 48 W/m K

Plate thickness = 100mm

Thus,L = 100/2 = 50mm = 0.05 m

Let's find the biot number from the formula;

Bi = hL/K

Bi = (250 × 0.05)/48

Bi = 0.2604

Now, lowest temperature in the slab is given as;

θ_o = (T_o - T∞)/(T_i - T∞)

θ_o = (550 - 800)/(200 - 800)

θ_o = 0.4167

Now, from online tables calculation, we can find the root of the biot number.

Thus, root of the biot number Bi = 0.2604 is;

ζ1 = 0.488 rad

Also, C1 is gotten as 1.0396

Now,formula for thermal diffusivity is;

α = k/ρc

α = 48/(7830 × 550)

α = 1.115 × 10^(-5) m²/s

Also, from online tables, f(ζ1) = 0.401

Thus, we can find the time the plate should the plate be left in the furnace from;

-(ζ1)²(αt/L²) = In 0.401

-(ζ1)²(αt/L²) = -0.9138

t = (-0.9138 × 0.05²)/-(0.488² × 1.115 × 10^(-5))

t ≈ 860 s

3 0

3 years ago

the second question. the answer to the first part is 616. pls i have a 34 on the assignment rn pls help

Marat540 [252]

Answer:

a) Ffloor = 616.56[N]

b) Ffloor = 484.16 [N]

Explanation:

In order to solve this problem, we must first make a free body diagram. In this free body diagram include forces, as well as acceleration.

Then after the free body diagram, we perform a force analysis by means of Newton's second law, where the upward forces and even the upward acceleration will be taken as positive.

ΣF = m*a

where:

F = force [N] (units of Newtons]

m = mass [kg]

a = acceleration [m/s²]

g = gravity acceleration = 9,81 [m/s²]

a)

$F_{floor} -m*g = m*a$

$F_{floor} -(56*9.81)=56*1.2\\F_{floor}= 616.56[N]$

b) Using Newton's second law we have.

$F_{floor}-m*g= -m*a\\F_{floor}=-m*a+m*g\\F_{floor} = -(56*1.2) + (56*9.81)\\F_{floor} = 484.16 [N]$

5 0

3 years ago

PLEASE HELP!! WORTH A TOTAL OF 100 POINTS!!

Serjik [45]

The last equation gives you the tension in the string on the right:

$T_2 = 2Mg - 2Ma = 2M (g-a) = \boxed{33.2 \, \mathrm N}$

4 0

2 years ago

What type of interaction allows the sidewalk to heat up and cook the egg?

Bogdan [553]

Answer:

Adsorption

Explanation:

Sidewalk cooking of egg is very popular in America. In summer people release fireworks in night sky and cook egg on the concrete sidewalk to check the level of temperature. When sunlight fall on the sidewalk most of the light is reflected back but some darker material adsorbs some photon, and when these photons are transferred to egg molecules it causes vibration among them and produce heat and cook egg.

7 0

3 years ago

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