Consider a fuel cell vehicle. The vehicle draws 30 kW of power at 60 mph and is 40% efficient at rated power. (It converts 40% of the energy stored in the hydrogen fuel to electric power.) You are asked to size the fuel cell system so that a driver can go at least 300 miles at 60 mph before refueling. Specify the minimum volume and weight requirements for the fuel cell system (fuel cell + fuel tank) given the following information:

• Fuel cell power density: 1 kW/L
• Fuel tank energy density (compressed hydrogen): 4 MJ/L

Answers

Answer 1

Answer:

minimum volume = 367.5 lit

minimum weight = 228.75 kg


Related Questions

A composite shaft with length L = 46 in is made by fitting an aluminum sleeve (Ga = 5 x 10^3 ksi) over a
steel core (Gs = 11 x10^3 ksi). The composite shaft is fixed against rotation at the wall A and has outside diameter da = 5 in. The steel core has diameter ds = 4 in. A torque TB = 3 kip. in is applied at B. % Matlab input: L = 46 Ga = 5 * 10^3 Gs = 11 * 10^3; da = 5; ds = 4; Tb = 3;
Determine the magnitude of the angle of twist at end B.

Answers

Answer:

Explanation:

Given the data in the question;

L = 46 in

Ga = 5 × 10³ ksi

Gs = 11 × 10³ ksi

Outside diameter da = 5 in

ds = 4 in

Tb = 3 kip.in

Now,

Ja = polar moment of Inertia of Aluminum;

Ja ⇒ π/32( 5⁴ - 4⁴ ) = π/32( 625 - 256 ) = π/32( 369 ) [tex]in^u[/tex]

Js = polar moment of inertia of steel

Js ⇒ π/32 ds⁴ = π/32( 4⁴ ) = π/32( 256 )

Ta is torque transmitted by Aluminum  

Ts is torque transmitted by steel  

{composite member }

T = Ta + Ts ------ let this be equation m1

Now, we use the relation;

T/J = G∅/L

JG∅ = TL

∅ = TL/GJ

so, for aluminum rod ∅[tex]_{alu[/tex] = TaLa/GaJa

for steel rod ∅[tex]_{steel[/tex] = TsLs/GsJs

but we know that, ∅a = ∅s = ∅[tex]_B[/tex]

so

[TaLa/GaJa]  =  [TsLs/GsJs]

also, we know that, La = Ls = L

∴ [Ta/GaJa]  =  [Ts/GsJs]

we solve for Ta

TaGsJs = TsGaJa  

Ta = TsGaJa / GsJs

we substitute

Ta = [Ts(5 × 10³)( π/32( 369) )] / [ (11 × 10³)( π/32( 256 ) ) ]

Ta = 0.66Ts

now, we substitute 0.66Ts for Ta and 3 for T in equation 1

T = Ta + Ts

3 = 0.66Ts + Ts

3 = 1.66Ts

Ts = 3 / 1.66

Ts = 1.8072 ≈ 1.81 kip-in

so

∅[tex]_{steel[/tex] = TsLs / GsJs

we substitute

∅[tex]_{steel[/tex] = (1.81 × 46 ) / ( 11 × 10³ × π/32( 256 ) )

∅[tex]_{steel[/tex] = 83.26 / 276460.1535

∅[tex]_{steel[/tex]  = 0.000301

∅[tex]_{steel[/tex] = 3.01 × 10⁻⁴ rad

so

[tex]_{steel[/tex] = ∅[tex]_B[/tex] = 3.01 × 10⁻⁴ rad

Therefore, the magnitude of the angle of twist at end B is 3.01 × 10⁻⁴  rad

Which part of a machine control unit interacts with the machine tools through electric signals?=]

A machine control unit is the electronic hardware that stores information and controls the machine tools. This unit contains a data processing unit that stores and manipulates data, and a ___________ that interacts with the machine tools through electrical signals.

Answers

Answer:

control loop unit

Explanation:

Edmentum/Plato

two ways in accepting responsibility can help teenagers to maintain coach relations with parents​

Answers

Answer:

1. It will help the teenagers gain the trust of their parents

2. It will help the teenagers obtain more privileges from their parents.

Explanation:

Responsibility is the state of accepting blame for a particular thing. A teenager who accepts responsibilities owns up to his mistakes and takes control over situations he is assigned to.

When teenagers accept responsibility for their actions, it helps the speaker to gain the trust of his parents who coach him in life. This trust will enable the parents to assign greater privileges to the teenagers because they believe they can handle them. Responsible teenagers do not engage in reckless activities.

When you measure
with a multimeter, you must break open the circuit and connect the meter's test leads in series with other circuits components
A. voltage
B. power
C. current
D. resistance

Answers

Answer:

resistance

Explanation:

so as to determine the reading

How would I get this python code to run correctly? it's not working.​

Answers

Answer:

See Explanation

Explanation:

This question requires more information because you didn't state what the program is expected to do.

Reading through the program, I can assume that you want to first print all movie titles then prompt the user for a number and then print the move title in that location.

So, the correction is as follows:

Rewrite the first line of the program i.e. movie_titles = ["The grinch......."]

for each_movie_titles in movie_titles:

   print(each_movie_titles)

   

usernum = int(input("Number between 0 and 9 [inclusive]: "))

if usernum<10 and usernum>=0:

   print(movie_titles[usernum])

Line by line explanation

This iterates through the movie_titles list

for each_movie_titles in movie_titles:

This prints each movie title

   print(each_movie_titles)

This prompts the user for a number between 0 and 9    

usernum = int(input("Number between 0 and 9 [inclusive]: "))

This checks for valid range

if usernum<10 and usernum>=0:

If number is valid, this prints the movie title in that location

   print(movie_titles[usernum])

Technician A says that ultra-high-strength steels (UHSS) are generally defined as those steels with tensile strengths greater than 700 MPa.
Technician B says that advanced high-strength steels (AHSS) are generally defined as those steels with tensile strengths from 375 MPa up to 1700
Who is right?
O A only
OB only
O Both A and B
O Neither A norb
Table of Contents

Answers

b only i think i’m not fully sure.

Stefan Lano needs displays that will show the musical instrument inventory in his chain of music stores that caters to musicians playing in world-class symphony orchestras in Basel, Switzerland; Buenos Aires, Argentina; and Philadelphia and New York in the United States. Design a form-fill interface for the inventory control of musical instruments in all four stores that could be used on a computer display screen. Assume that English will be the interface language.

Answers

Answer:

attached below is an example of  the form

Explanation:

This type of form-fill can be described/developed based on the requirements or information needed by the organization in order to perfectly fulfill an order  and also to retain customers by making the form very easy and interactive attached below is an example of such form fill  interface

explain the working and performance of a centrifugal clutch with a sketch​

Answers

Answer:

A centrifugal clutch works, as the name suggests, through centrifugal force.

One of the most common methods is by mounting the clutch onto the parallel or taper crank shaft of the engine.

When the crank shaft rotates the shaft of the clutch rotates at the same speed as the engine

Designing is a way to generate solutions to a real-world problem experienced by humans.
True

False

Answers

True,My good sir/maam

Which of the following can cause a flopping sound at the front of the engine
A) drive belt too loose
B) timing chain too loose
C) drive belt too tight
D) timing chain too tight

Answers

B) timing chain too loose

A rigid insulated tank is divided into 2 equal compartments by a thin rigid partition. One of the compartments contains air, assumed to be an ideal gas at 800 kPa and 300 K. The other compartment is under a vacuum. The partition is suddenly broken and the air rushes into the evacuated compartment. The tank pressure and temperature eventually equilibrate.

a. Define the system you will use and draw a labeled schematic.
b. Write the energy balance for the system, making simplifications as appropriate.
c. What is the final temperature of the gas, K?
d. What is the final pressure, kPa?

Answers

https://www.slader.com/discussion/question/an-insulated-rigid-tank-is-divided-into-two-equal-parts-by-a-partition-initially-one-part-contains-4/



there will be the answer

Can be used to eliminate rubbing friction of wheel touching frame. 1.Traction 2.Thrust washer

Answers

Answer:

thrust washer

can be used to eliminate rubbing friction of wheel touching frame

IF A CAR AHEAD OF YOU HAS STOPPED AT A CROSSWALK, YOU SHOULD:
A. Stop and then proceed when safe

B. Change lanes, look carefully, and pass

C. Slow down, look both ways, and proceed

D. Drive to the right edge of the road and stop

HELP PLZ

Answers

Answer:

well, depend if theres a stop sign or a light signal..you can always just honk at him/her so they proceed

Explanation:

but otherwise, the answer would be

A: stop and proceed when safe

Hope this helped! Have a nice day, and feel free to follow me on insta (leo_g_rios)

-XxDeathshotxX

A baker deck decorates 42 cupcakes and 30 minute she decorated cupcakes at a constant rate how many cups cage the baker decorate pre-minute

Answers

Answer: 1.4 cupcakes per minute.

Explanation:

Here's the correct question:

A baker decorates 42 cupcakes in 30 minutes. How many cupcakes can the baker decorate per minute?

Since the baker decorates 42 cupcakes in 30 minutes, the number of cupcakes that the baker decorates for each minutes since it's at a constant rate will be the total number of cupcakes made divided by the number of minutes. This will be:

= 42cupcakes / 30minutes

= 1.4 cupcakes per minute.

Therefore, the number of cupcakes that the baker can decorate per minute is 1.4cupcakes/minute

The housing for a certain machinery product is made of two components, both aluminum castings. The larger component has the shape of a dish sink and the second component is a flat cover that is attached to the first component to create an enclosed space for the machine parts. Sand casting is used to produce the two castings, both of which are plagued by defects in the form of misruns and cold shuts. The shop supervisor complains that the thicknesses of the parts are too thin, and that is the reason for the defects. However, it is known that the same components are cast successfully in other foundries. What explanations can be given for the defects

Answers

Answer:

The pouring of the molten metal during casting is done very slowly hence the molten metal froze before reaching all parts of the mould cavity. also the early freezing can occur if the temperature of the molten metal was lower than the required temperature for casting

Explanation:

since the same components are being casted at other foundries and they don't have the defects ,

Hence the reason for the defects experienced by these components can be caused when the pouring of the molten metal during casting is done very slowly hence the molten metal froze before reaching all parts of the mould cavity. also the early freezing can occur if the temperature of the molten metal was lower than the required temperature for casting .

A transformer is to be used to provide power for a computer disk drive that needs 6.4 V (rms) instead of the 120 V (rms) from the wall outlet. The number of turns in the primary is 300, and it delivers 500 mA (the secondary current) at an output voltage of 6.4 V (rms). (a) Should the transformer have more turns in the secondary compared to the primary, or fewer turns

Answers

Answer:

The secondary coil should have fewer turns compared to the primary coil.

Explanation:

[tex]N_p[/tex] = Number of turns in primary coil = 300

[tex]N_s[/tex] = Number of turns in secondary

[tex]V_p[/tex] = Voltage in primary coil = 120 V

[tex]V_s[/tex] = Voltage in secondary coil = 6.4 V

We have the relation

[tex]\dfrac{N_p}{N_s}=\dfrac{V_p}{V_s}\\\Rightarrow N_s=\dfrac{N_p}{V_p}\times V_s\\\Rightarrow N_s=\dfrac{300}{120}\times 6.4\\\Rightarrow N_s=16[/tex]

The secondary coil has 16 turns which is less than the turns in the primary coil.

Explain the importance of water quality in aquaculture business.

Answers

Answer:

this is very important the agricultural because there can be a risk of hight salt concentrations that can limit the amount of water plants can take

Answer:

Mantain the image of the business

Explanation:

Good water quality gives good images to others and furthers business

A jet aircraft is in level flight at an altitude of 30,000 ft with an airspeed of 500 ft/s. The aircraft has a gross weight of 19,815 lb, a wingspan of 53.3 ft, and an average chord length of 6 ft. The Oswald efficiency factor is 0.81 and the zero-lift drag coefficient is equal to 0.02. The jet has two turbofan engines, each producing a maximum thrust of 3,650 lb at sea level.

Required:
a. Create a plot of the drag polar for this aircraft for CL from 0 to 5. Plot CL on the vertical axis, CD on the horizontal axis, and do not include negative CL values.
b. What is the total drag coefficient at the flight condition described above?
c. What is the required thrust for level flight at this altitude in lb?
d. If the pilot runs the engines at maximum thrust, what is the instantaneous rate of climb at this altitude and velocity?

Answers

Answer:

a) attached below

b) 0.0337

c) 2730.206 Ib

d) 2320.338 ft/min

Explanation:

a) Plot of the drag polar for this aircraft

first we will calculate :

Wing area (s) = Wing span (b) * Average chord length(c)

                       = 53.3 * 6 = 319.8 ft^2

Aspect ratio =  b^2 / s = 8.883

K = 1 / [tex]\pi[/tex]eAR = 1 /

Drag polar ( Cd ) = 0.02 + 0.044 C^2L

attached below is a plot of the drag polar

Attached below is the detailed solution of the remaining part of the question

Q.13 In order to produce maximum starting torque in a split-phase motor, how many degrees out of phase should the start- and run-winding currents be with each other?
Select one:
A. 180°
B. 0°
C. 120°
D. 90°

Answers

Answer:

D. 90 degrees.

Explanation:

Torque is a rotational force which moves an object in other direction. There should be 90 degrees out of phase to start, run winding currents with each other. Torque is produced by the rotational motion of an object. The angle of the object must be 90 degrees set in order to create torque.

A current value of 0.000005 A is equal to
Α. 50 μΑ. .
B. 5 mA.
C.5 HA.
D. 50 mA.

Answers

The correct answer is letter C

A current value of 0.000005 A is equal to 5 HA.

What is Current?

Current is a measure of rate. In physics, there are various rate quantities. For instance, velocity, which measures how quickly an item changes position, is a rate quantity.

Velocity is defined mathematically as the position change to time ratio. The rate at which an object changes its velocity is called acceleration, which is a rate quantity.

Acceleration is defined mathematically as the ratio of velocity change to time. Power, which measures the rate at which work is done on an object, is a rate quantity.

A current value of 0.000005 A is equal to 5 HA.

To learn more about current, refer to the link:

https://brainly.com/question/13076734

#SPJ2

There are gauges available for checking panel flushness. TRUE OR FALSE?

Answers

Answer: true

Explanation:

because flushness means your dead   so you are dead now

There are gauges available for checking panel flushness. to allow for front-to-back movement. to allow for side-to-side movement. for height adjustments. So yes it is true. Hope this helps!

write three ways of soil investigation of a site​

Answers

Methods of Soil Exploration
Open excavation.
Borings.
Subsurface soundings.
Geographical methods.

A hydraulic jump is formed in a 4m wide outlet just downstream of a control gate, which is located at the upstream end of the outlet. The flow depth upstream of the gate is 20 m. Assume there are no losses in the flow through the gate. If the outlet discharge is 40 m3/s, determine (6 points)a. Flow depth downstream of the jump (y1)b. Energy losses in the jump (between y1 and y2).

Answers

Answer:

Width w = 4m

Glow depth = y1 = 20m

Outlet discharge = 40m

V1= velocity of flow = 40/20*4 = 1/2 = 0.5m/s

Froud number = v1/√gy1

= 0.5/√9.81x20 = 0.0356

1. Y2/20 = 1/2[-1+√1+8*(0.0356)²]

Y2 = 0.05

2. Energy loss in the jump = (20-0.05)²/4x20x0.05

= 1985m

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

Answers

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

Answer: yayyyy free sh.it

Explanation:

8. Which of these plastics is a themoplastic - melts or softens with heat.
Acrylic
Bakelite
Polyester resin
Melamine
Epoxy Resin

Could someone please help me, this is very urgent, I will pay an extra bonus if done correct.

Answers

Answer:

Acryclic

Explanation:

Hope it helps you!

7.13 An intersection approach has a saturation flow rate of 1500 veh/h, and vehicles arrive at the approach at the rate of 800 veh/h. The approach is controlled by a pretimed signal with a cycle length of 60 seconds and D/D/1 queuing holds. Local standards dictate that signals should be set such that all approach queues dissipate 10 seconds before the end of the effective green portion of the cycle. Assuming that approach capacity exceeds arrivals, determine the maximum length

Answers

Answer:

23.34 seconds

Explanation:

Flow rate = 1500

Arrival = 800 vehicle per hour

Cycle c = 60 seconds

Dissipation time = 10 seconds

Arrival time = 800/3600 = 0.2222

Rate of departure = 1500/3600 = 0.4167

Traffic density p = 0.2222/0.4167 = 0.5332

Real time = r

r + to + 10 = c

to = c-r-10 ----1

t0 = p*r/1-p ----2

Equate both 1 and 2

C-r-10 = p*r/1-p

60-r-10 = 0.5332r/1-0.5332

50-r = 0.5332r/0.4668

50-r = 1.1422r

50 = 1.1422r + r

50 = 2.1422r

r = 50/2.1422

r = 23.34 seconds

Two kilograms of air in a piston-cylinder assembly undergoes an isothermal
process from an initial state of 200 K, 300 kPa to 600 kPa.
How much work is done during the process, in kj?​

Answers

Answer:

a) 0.39795 kJ/K

b) 79.589.37 kJ

Explanation:

m = Mass of air = 2 kg

Temperature = 200 K

P₁ = Initial pressure = 300 kPa

P₂ = Final pressure = 600 kPa

R = mass-specific gas constant for air = 287.058 J/kgK

a) For isentropic process

∴ Entropy is generated in the process is 0.39795 kJ/K

b)

∴ Amount of lost work is 79.589.37 kJ

Hot engine oil with heat capacity rate of 4440 w/k (product of mass flow rate and specific heat) and an inlet temperature of 150°c flows through a double pipe heat exchanger. the double pipe heat exchanger is constructed of a 1.5-m-long copper pipe (k = 250 w/m·k) with an inner tube of inside diameter 2 cm and outside tube diameter of 2.25 cm. the inner diameter of the outer tube of the double pipe heat exchanger is 6 cm. oil flowing at a rate of 2 kg/s through inner tube exits the heat exchanger at a temperature of 50°c. the cold fluid, i. e., water enters the heat exchanger at 20°c and exits at 70°c. assuming the fouling factor on the oil side and water side to be 0.00015 m2 ·k/w and 0.0001 m2 ·k/w, respectively, determine the overall heat transfer coefficient on inner and outer surface of the copper tube.

Answers

Explanation:

fluid, i. e., water enters the heat exchanger at 20°c and exits at 70°c. assuming the fouling factor on the oil side and water side to be 0.00015 m2 ·k/w and 0.0001 m2 ·k/w, respectively, determine the overall heat transfer coefficient on inner and outer surface of the copper tube.xgjicbb .follow me

The tensile strength of brittle materials may be determined using a variation of Equation 8.1. Compute the critical crack tip radius for an Al2O3 specimen that experiences tensile fracture at an applied stress of 275 MPa (40,000 psi). Assume a critical surface crack length of 2 × 10−3 mm and a theoretical fracture strength of E/10, where E is the modulus of elasticity.

Answers

Answer:

0.39 nM

Explanation:

The critical crack tip radius from the equation

attached below

for fracture to occur the бm will have to reach the fracture strength of material

i.e.  бm =  E/10

from equation 2 attached below

St = ( 400 * a * бo^2 ) / E^2 ------ 3

Given : a = 2*10^-3 mm , бo = 275 MPa, E = 393 * 10^3 MPa ( gotten from table)

Input given values into equation 3

St = 3.9 * 10^-7 ≈ 0.39 nM

The inverted U-tube is used to measure the pressure difference between two points A and B in an inclined pipeline through which water flows. The differenceof level h=0.4m ; X=0.2; and Y=0.3m. Calculate the pressure difference between point B and A if the top of the manometer is filled with:
i) Air
ii) paraffin of relative density of 0.75

Answers

Answer:

i) 0.610 m or 610 mm

ii) 0.4 m or 400 mm

Explanation:

The pressure difference between the pipes is

a) Air

Pa + πha +Ha = Pb + πhb +Hb

Pa - Pb = π(hb-ha) + Hb-Ha

Relative density of air = 1.2754 kg /m3

Pa - Pb = 1.2754 * 0.4 + (0.3-0.2) = 0.610 m or 610 mm

b) paraffin of relative density of 0.75

Pa - Pb = π(hb-ha) + Hb-Ha

Pa - Pb = 0.75 * 0.4 + (0.3-0.2) = 0.4 m or 400 mm

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