90% of traffic crashes are due to driver error.<br> True<br> False

A 65% efficient turbine receives 2 m^3/s of water from a reservoir. The reservoir water surface is 45 m above the centerline of

laiz [17]

Answer:

$P_{out} = 508.071 kW$

Given:

efficiency of the turbine, $\eta$ = 65% = 0.65

available gross head, $H_{G}$ = 45 m

head loss, $H_{loss}$ = 5 m

Discharge, Q = $2 m^{3}$

Solution:

The nozzle is 100% (say)

Available power at the inlet of the turbine, $P_{inlet}$ is given by:

$P_{inlet} = \rho Qg(H_{G} - H_{loss})$ (1)

where

$\rho$ = density of water = 997 $kg/m^{3}$

acceleration due to gravity, g = $9.8 m^{2}$

Using eqn (1):

$P_{inlet} = 997\times 2\times 9.8(45 - 5) = 781.65 kW$

Also, efficency, $\eta$ is given by:

$\eta = \frac{P_{out}}{P_{inlet}}$

$0.65 = \frac{P_{out}}{781.648\times 1000}$

$P_{out} = 0.65\times 781.648\times 1000 = 508071 W = 508.071 kW$

$P_{out} = 508.071 kW$

3 0

3 years ago

Mechanical clips are used to close bags and keep things together. Investigate the design of various paper clips, hair clips, and

pochemuha

Answer:

Hair clip: this used to hold human hairs together especially long hairs

The Design parameters to be considered are : number of teeth, durability of the material to be used and also the width ( how wide the clip can open )

Advantages : very easy to use, holds hairs tight

Disadvantages : Expensive and material used is sometimes brittle

paper clips : This used to hold papers together it is made of a thin elastic wire

The design parameters to be considered are : length of the wire, material to be used and the elasticity of the material

advantages : it is quite cheap and good strength

disadvantages :it can hold a limited amount of papers together

potato chip bag clips: These clips are used on potato chip bags to ensure that the bags are air tight

The design parameters to be considered are : Elasticity of the material to be used , and size

Advantages : it helps to prevent the potato chips from getting exposed to air

disadvantages : Not very popular and its quite expensive

Explanation:

Hair clip: this used to hold human hairs together especially long hairs

The Design parameters to be considered are : number of teeth, durability of the material to be used and also the width ( how wide the clip can open )

Advantages : very easy to use, holds hairs tight

Disadvantages : Expensive and material used is sometimes brittle

paper clips : This used to hold papers together it is made of a thin elastic wire

The design parameters to be considered are : length of the wire, material to be used and the elasticity of the material

advantages : it is quite cheap and good strength

disadvantages :it can hold a limited amount of papers together

potato chip bag clips: These clips are used on potato chip bags to ensure that the bags are air tight

The design parameters to be considered are : Elasticity of the material to be used , and size

Advantages : it helps to prevent the potato chips from getting exposed to air

disadvantages : Not very popular and its quite expensive

4 0

3 years ago

Helium gas is compressed from 90 kPa and 30oC to 450 kPa in a reversible, adiabatic process. Determine the final temperature and

ra1l [238]

Answer:

T2 ( final temperature ) = 576.9 K

a) 853.4 kJ/kg

b) 1422.3 kJ / kg

Explanation:

given data :

pressure ( P1 ) = 90 kPa

Temperature ( T1 ) = 30°c + 273 = 303 k

P2 = 450 kPa

Determine final temperature for an Isentropic process

$T2 = T1 (\frac{p2}{p1} )^{(k-1)/k}$ ----------- ( 1 )

T2 = 303 $( \frac{450}{90})^{(1.667- 1)/1.667}$ = 576.9K

Work done in a piston-cylinder device can be calculated using this formula

$w_{in} = c_{v} ( T2 - T1 )$ ------- ( 2 )

where : cv = 3.1156 kJ/kg.k for helium gas

T2 = 576.9K , T1 = 303 K

substitute given values Back to equation 2

$w_{in}$ = 853.4 kJ/kg

work done in a steady flow compressor can be calculated using this

$w_{in} = c_{p} ( T2 - T1 )$

where : cp ( constant pressure of helium gas ) = 5.1926 kJ/kg.K

T2 = 576.9 k , T1 = 303 K

substitute values back to equation 3

$w_{in}$ = 1422.3 kJ / kg

4 0

3 years ago

¿Qué es la masonería?

timofeeve [1]

Answer: freemasonry is Being a Mason is about a father helping his son make better decisions; a business leader striving to bring morality to the workplace; a thoughtful man learning to work through tough issues in his life.

Explanation:

3 0

3 years ago

Which symbol should be used for the given scenario?

Firdavs [7]

Answer:

speed square

Explanation:

4 0

3 years ago

90% of traffic crashes are due to driver error. True False