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What was the most recent technological shift in society

SOVA2 [1]

Answer:

people and the internet – people’s association and interaction with the web as a mental, social and physical extension of themselves i think

Explanation:

8 0

3 years ago

Air is flowing steadily through a cooling section where it is cooled from 30 °C to 15 °C at a rate of 0.25 kg/s.

Lady bird [3.3K]

Answer:

$C_{day} = 2.261\,USD$

Explanation:

The heat transfer rate rejected to the refrigeration system is:

$\dot Q_{L} = (0.25\,\frac{kg}{s} )\cdot (1.005\,\frac{kJ}{kg\cdot ^{\textdegree}C} )\cdot (30\,^{\textdegree}C-15\,^{\textdegree}C)$

$\dot Q_{L} = 3.768\,kW$

The electric power needed to make refrigeration possible is:

$\dot W = \frac{\dot Q_{L}}{COP_{R}}$

$\dot W = \frac{3.768\,kW}{2.8}$

$\dot W = 1.346\,kW$

The daily energy consumption is:

$\Delta E_{day} = (1.346\,kW)\cdot (86400\,s)$

$\Delta E_{day} = 116294.4\,kJ$

$\Delta E_{day} = 32.304\,kWh$

The cost of electricity consumed by the air-conditioner per day is:

$C_{day} = c\cdot \Delta E_{day}$

$C_{day} = (0.07\,\frac{USD}{kWh} )\cdot (32.304\,kWh)$

$C_{day} = 2.261\,USD$

5 0

3 years ago

Read 2 more answers

Use pseudocode. 1) Prompt for and input a saleswoman's sales for the month (in dollars) and her commission rate (percentage). Ou

aleksandr82 [10.1K]

Answer:

The pseudocode is as follows:

Input SalesAmount

Input CommissionRate

CommissionEarned= SalesAmount * (CommissionRate/100)

Print CommissionEarned

Explanation:

This gets input for SalesAmount

Input SalesAmount

This gets input for CommissionRate

Input CommissionRate

This calculates the CommissionEarned

CommissionEarned= SalesAmount * (CommissionRate/100)

This prints the calculated CommissionEarned

Print CommissionEarned

3 0

3 years ago

Consider a steam turbine, with inflow at 500oC and 7.9 MPa. The machine has a total-to-static efficiency ofηts=0.91, and the pre

sergiy2304 [10]

Answer: $\dot m_{in} = 23.942 \frac{kg}{s}$ , $\dot H_{out} = 39632.62 kW$

Explanation:

Since there is no information related to volume flow to and from turbine, let is assume that volume flow at inlet equals to $\dot V = 1 \frac{m^{3}}{s}$ . Turbine is a steady-flow system modelled by using Principle of Mass Conservation and First Law of Thermodynamics:

Principle of Mass Conservation

$\dot m_{in} - \dot m_{out} = 0$

First Law of Thermodynamics

$- \dot W_{out} + \eta\cdot (\dot m_{in} \dot h_{in} - \dot m_{out} \dot h_{out}) = 0$

This 2 x 2 System can be reduced into one equation as follows:

$-\dot W_{out} + \eta \cdot \dot m \cdot ( h_{in}- h_{out})=0$

The water goes to the turbine as Superheated steam and goes out as saturated vapor or a liquid-vapor mix. Specific volume and specific enthalpy at inflow are required to determine specific enthalpy at outflow and mass flow rate, respectively. Property tables are a practical form to get information:

Inflow (Superheated Steam)

$\nu_{in} = 0.041767 \frac{m^{3}}{kg} \\h_{in} = 3399.5 \frac{kJ}{kg}$