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3 years ago

Help me how do you do this ?? ASAP HELPPPP

Physics

1 answer:

Nataly [62]3 years ago

8 0

cant really answer here with text but at the top of the slide it should br positives and towards the bottom its negative.

This is because you go faster at the top of the slide than the bottom and when your at the bottom you slow down

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A counterflow double-pipe heat exchanger is used to heat water from 20°C to 80°C at a rate of 1.2 kg/s. The heating is to be com

bixtya [17]

Answer:L=109.16 m

Explanation:

Given

initial temperature $=20^{\circ}C$

Final Temperature $=80^{\circ}C$

mass flow rate of cold fluid $\dot{m_c}=1.2 kg/s$

Initial Geothermal water temperature $T_h_i=160^{\circ}C$

Let final Temperature be T

mass flow rate of geothermal water $\dot{m_h}=2 kg/s$

diameter of inner wall $d_i=1.5 cm$

$U_{overall}=640 W/m^2K$

specific heat of water $c=4.18 kJ/kg-K$

balancing energy

Heat lost by hot fluid=heat gained by cold Fluid

$\dot{m_c}c(T_h_i-T_h_e)= \dot{m_h}c(80-20)$

$2\times (160-T)=1.2\times (80-20)$

$160-T=36$

$T=124^{\circ}C$

As heat exchanger is counter flow therefore

$\Delta T_1=160-80=80^{\circ}C$

$\Delta T_2=124-20=104^{\circ}C$

$LMTD=\frac{\Delta T_1-\Delta T_2}{\ln (\frac{\Delta T_1}{\Delta T_2})}$

$LMTD=\frac{80-104}{\ln \frac{80}{104}}$

$LMTD=91.49^{\circ}C$

heat lost or gain by Fluid is equal to heat transfer in the heat exchanger

$\dot{m_c}c(80-20)=U\cdot A\cdot$ (LMTD)

$A=\frac{1.2\times 4.184\times 1000\times 60}{640\times 91.49}=5.144 m^2$

$A=\pi DL=5.144$

$L=\frac{5.144}{\pi \times 0.015}$

$L=109.16 m$

6 0

3 years ago

A solenoid of length 2.50 cm and radius 0.750 cm has 25 turns. If the wire of the solenoid has 1.85 amps of current, what is the

vfiekz [6]

Answer:

13.875 T

Explanation:

Parameters given:

Length of solenoid, L = 2.5 cm = 0.025 m

Radius of solenoid, r = 0.75 cm = 0.0075 m

Number of turns, N = 25 turns

Current, I = 1.85 A

Magnetic field, B, is given as:

B = (N*r*I) /L

B = (25 * 0.0075 * 1.85)/0.025

B = 13.875 T

4 0

3 years ago

Give two examples of chemical energy being transformed into electrical energy

julsineya [31]

It can be used to create electricity and heat and can be found in propane , jet fuel, gasoline and other products. Wood - Dry wood stores chemical energy . This chemical energy is released as the wood burns, and it is burns, and it is converted into heat, which is also called thermal energy, and light energy. ( hope this be helpful)

7 0

3 years ago

Why is the following situation impossible? The object of mass m = 4.00 kg in Figure P6.10 is attached to a vertical rod by two s

Crank

The situation is impossible mainly because we can't see Figure P6.10 .
It would undoubtedly be the same story on an another planet, until we
see the figure and understand what's going on.

4 0

3 years ago

Motor oil , with a viscosity of 0 . 250 Ns / m2 , is flowing through a tube that has a radius of 5 . 00 mm and is 25 . 0 cm long

Thepotemich [5.8K]

Answer:

1.1775 x 10^-3 m^3 /s

Explanation:

viscosity, η = 0.250 Ns/m^2

radius, r = 5 mm = 5 x 10^-3 m

length, l = 25 cm = 0.25 m

Pressure, P = 300 kPa = 300000 Pa

According to the Poisuellie's formula

Volume flow per unit time is

$V=\frac{\pi \times Pr^{4}}{8\eta l}$

$V=\frac{3.14 \times 300000\times \left ( 5\times 10^{-3} \right )^{4}}{8\times 0.250\times 0.25}$

V = 1.1775 x 10^-3 m^3 /s

Thus, the volume of oil flowing per second is 1.1775 x 10^-3 m^3 /s.

3 0

3 years ago