Answer:
64000 lb
Explanation:
A square concrete column is 4 in by 4 in cross-section and is subject to a compressive load P. If the compressive stress cannot exceed 4000 psi and the shear stress cannot exceed 1500 psi.
The area of the square concrete column = 4 in × 4 in = 16 in²
The compressive stress (σ) cannot exceed 4000 psi.
Compressive stress is the ratio of load applied to the area. Therefore the maximum load is the product of the maximum compressive stress and the area. The maximum compressive stress is given as:
[tex]\sigma_{max}=\frac{P_{max}}{Area} \\P_{max}= \sigma_{max}*Area\\P_{max}=4000\ psi *16\ in^2\\P_{max}=64000\ lb[/tex]
Therefore the maximum allowable load P is 64000 lb
Many HVACR industry publications are published by
Answer:
HVACR Industry Trade Groups
Explanation:
A ball bearing has been selected with the bore size specified in the catalog as 35.000 mm to 35.020 mm. Specify appropriate minimum and maximum shaft diameters to provide a locational interference fit.
Answer:
A ball bearing has been selected with the bore size specified in the catalog as 35.000 mm to 35.020 mm. Specify.... ... has been selected with the bore size specified in the catalog as 35.000 mm to 35.020 mm. Specify appropriate minimum and maximum shaft diameters to provide a locational interference fit.
Explanation:
The liquid-phase reaction A + B → C follows an elementary rate law and is carried out isothermally in a flow system. The concentrations of A and B feed streams are 2 M before mixing. The volumetric flow rate of each stream is 5 dm3 /min and the entering temperature is 300 K. The streams are mixed immediately before entering. Two reactors are available: One is a gray 200.0 dm3 CSTR that can be heated to 77°C or cooled to 0°C, and the other is a white 800.0 dm3 PFR operated at 300 K that cannot be heated or cooled but can be painted red or black. (Note: k = 0.07 dm3 /mol*min at 300 K and E = 20 kcal/mol.) How long would it take to achieve 90% conversion in a 200 dm3 batch reactor with CA ° = CB ° = 1 ???? after mixing at a temperature of 70°C?
Answer:
1.887 minutes
Explanation:
We are given k = 0.07 dm3 /mol*min at 300 K and E = 20 kcal/mol = 20000 cal/mol
To solve this, first of all let's calculate the rate constant(k);
For this question, The formula is;
K(t) = k(300K) × exp[(E/R)((1/300) - (1/T2))]
R is gas constant = 1.987 cal/mol.K
For temperature of 70°C which is = 70 + 273K = 343K, we have;
K(343) = 0.07 × exp[(20000/1.987)((1/300) - (1/343))]
K(343) = 4.7 dm³/mol.min
The design equation is;
dX/dt = -(rA/C_Ao) = K•(C_Ao)²•(1 - X)²/(C_Ao) = (KC_Ao)(1 - X)²
Since there is no change in volume by cause of the state at which the reaction is carried out, that is liquid. Thus, integrating and solving for time for a 90% conversion we obtain;
(0.9,0)∫dX/(1 - X)².dX = (KC_Ao)((t, 0)∫dt
So, we'll get;
0.9/(1 - 0.9) = 4.77 × 1 × t
t = 9/4.77
t = 1.887 minutes
If the resistance reading on a DMM'S meter face is to 22.5 ohms in the range selector switch is set to R X 100 range, what is the actual measure resistance of the circuit?
Answer:
The answer is 2.25 kΩ
Explanation:
Solution
Given that:
The resistance reading on a DMM'S meter face = 22.5 ohms
The range selector switch = R * 100 range,
We now have to find the actual measure resistance of the circuit which is given below:
The actual measured resistance of the circuit is=R * 100
= 22.5 * 100
=2.25 kΩ
Hence the measured resistance of the circuit is 2.25 kΩ
In real world, sampling and quantization is performed in an analog to digital converter (ADC) and reconstruction is performed in a digital to analog converter (DAC). Which of the following statements hold true (fs denotes the sampling frequency)?
a. the reconstruction filter can be found in the DAQ
b. the antialiasing filter removes all frequencies of the continuous-time analog input signal that are above fs/2
c. the DAC needs to know the sampling frequency of the ADC to correctly reconstruct the signal.
d. the reconstructed continuous-time signal only contains frequencies up to fs/2
Answer:
b
Explanation:
a) ADC is located on DAQ filter but not the reconstruction filter
b) to remove aliasing, the sampling rate must be greater than or equal ot twice the highest frequency component in the input signal. In other words, all frequencies in input sgnal are less than fs/2. Therefore, frequencies greater than fs/2 are removed by anti-aliasing filter
c) the DAC can have different sampling rate from ADC
Air flows along a horizontal, curved streamline with a 20 foot radius with a speed of 100 ft/s. Determine the pressure gradient normal to the streamline.
Answer:
- 1.19 lb/ft^3
Explanation:
You are given the following information;
Radius r = 20 ft
Speed V = 100 ft/s
You should use Bernoulli equation pertaining to streamline. That is, normal to streamline.
The pressure gradient = dp/dn
Where air density rho = 0.00238 slugs per cubic foot.
Please find the attached files for the solution and diagram.
Instructions given by traffic police or construction flaggers _____. A. Are sometimes important to follow B. Are usually not important to follow C. Don't overrule laws or traffic control devices D. Overrule any other laws and traffic control devices
Answer:
D. Overrule any other laws and traffic control devices.
Explanation:
Laws and traffic control devices are undoubtedly compulsory to be followed at every point in time to control traffic and other related situations. However, there are cases when certain instructions overrule these laws and traffic control devices. For example, when a traffic police is giving instructions, and though the traffic control devices too (such as traffic lights) are displaying their own preset lights to control some traffic, the instructions from the traffic police take more priority. This is because at that point in time, the instructions from the traffic control devices might not be just applicable or sufficient.
Also, in the case of instructions given by construction flaggers, these instructions have priority over those from controlling devices. This is because during construction traffic controls are redirected from the norms. Therefore, the flaggers such be given more importance.
Answer:
D. Overrule any other laws and traffic control devices.
Explanation:
A two-dimensional flow field described by
V = (2x^2y + x)1 + (2xy^2 + y + 1 )j
where the velocity is in m/s when x and y are in meters. Determine the angular rotation of a fluid element located at x 0.5 m, y 1.0 m.
Answer:
the answer is
Explanation:
We now focus on purely two-dimensional flows, in which the velocity takes the form u(x, y, t) = u(x, y, t)i + v(x, y, t)j. (2.1) With the velocity given by (2.1), the vorticity takes the form ω = ∇ × u = ∂v ∂x − ∂u ∂y k. (2.2) We assume throughout that the flow is irrotational, i.e. that ∇ × u ≡ 0 and hence ∂v ∂x − ∂u ∂y = 0. (2.3) We have already shown in Section 1 that this condition implies the existence of a velocity potential φ such that u ≡ ∇φ, that is u = ∂φ ∂x, v = ∂φ ∂y . (2.4) We also recall the definition of φ as φ(x, y, t) = φ0(t) + Z x 0 u · dx = φ0(t) + Z x 0 (u dx + v dy), (2.5) where the scalar function φ0(t) is arbitrary, and the value of φ(x, y, t) is independent of the integration path chosen to join the origin 0 to the point x = (x, y). This fact is even easier to establish when we restrict our attention to two dimensions. If we consider two alternative paths, whose union forms a simple closed contour C in the (x, y)-plane, Green’s Theorem implies thatYou are given a body with no body forces and told that the stress state is given as: ⎡ ⎣ 3αx 5βx2 + αy γz3 5βx2 + αy βx2 0 γz3 0 5 ⎤ ⎦ psi, where (α, β, γ) are constants with the following values: α = 1 psi/in, β = 1 psi/in2, and γ = 1 psi/in3. Does this represent an equilibrium state of stress? Assume the body occupies the domain Ω = [0, 1] × [0, 1] × [0, 1] (in inches).
Answer:
This doesn't represent an equilibrium state of stress
Explanation:
∝ = 1 , β = 1 , y = 1
x = 0 , y = 0 , z = 0 ( body forces given as 0 )
Attached is the detailed solution is and also the conditions for equilibrium
for a stress state to be equilibrium all three conditions has to meet the equilibrum condition as explained in the attached solution
Air enters a compressor operating at steady state at 176.4 lbf/in.^2, 260°F with a volumetric flow rate of 424 ft^3/min and exits at 15.4 lbf/in.^2, 80°F. Heat transfer occurs at a rate of 6800 Btu/h from the compressor to its surroundings. Assuming the ideal gas model for air and neglecting kinetic and potential energy effects, determine the power input, in hp
Answer:
[tex]W_s =[/tex] 283.181 hp
Explanation:
Given that:
Air enters a compressor operating at steady state at a pressure [tex]P_1[/tex] = 176.4 lbf/in.^2 and Temperature [tex]T_1[/tex] at 260°F
Volumetric flow rate V = 424 ft^3/min
Air exits at a pressure [tex]P_2[/tex] = 15.4 lbf/in.^2 and Temperature [tex]T_2[/tex] at 80°F.
Heat transfer occurs at a rate of 6800 Btu/h from the compressor to its surroundings; since heat is released to the surrounding; then:
[tex]Q_{cv}[/tex] = -6800 Btu/h = - 1.9924 kW
Using the steady state energy in the process;
[tex]h_2 - h_1 + g(z_2-z_1)+ \dfrac{1}{2}(v^2_2-v_1^2) = \dfrac{Q_{cv}}{m}- \dfrac{W_s}{m}[/tex]
where;
[tex]g(z_2-z_1) =0[/tex] and [tex]\dfrac{1}{2}(v^2_2-v_1^2) = 0[/tex]
Then; we have :
[tex]h_2 - h_1 = \dfrac{Q_{cv}}{m}- \dfrac{W_s}{m}[/tex]
[tex]h_2 - h_1 = \dfrac{Q_{cv} - W_s}{m}[/tex]
[tex]{m}(h_2 - h_1) ={Q_{cv} - W_s}[/tex]
[tex]W_s ={Q_{cv} + {m}(h_2 - h_1)[/tex] ----- (1)
Using the relation of Ideal gas equation;
P₁V₁ = mRT₁
Pressure [tex]P_1[/tex] = 176.4 lbf/in.^2 = ( 176.4 × 6894.76 ) N/m² = 1216235.664 N/m²
Volumetric flow rate V = 424 ft^3/min = (424 × 0.0004719) m³ /sec
= 0.2000856 m³ /sec
Temperature = 260°F = (260°F − 32) × 5/9 + 273.15 = 399.817 K
Gas constant R=287 J/kg K
Then;
1216235.664 N/m² × 0.2000856 m³ /sec = m × 287 J/kg K × 399.817 K
[tex]m = \dfrac { 1216235.664 N/m^2 \times 0.2000856 m^3 /sec } {287 J/kg K \times 399.817 K }[/tex]
m = 2.121 kg/sec
The change in enthalpy:
[tex]m(h_1-h_2) = m * C_p * \Delta T= m* C_p * ( T_1 -T_2)[/tex]
[tex]= 2.121* 1.005* ( 399.817 -299.817)[/tex]
= 213.1605 kW
From (1)
[tex]W_s ={Q_{cv} + {m}(h_2 - h_1)[/tex]
[tex]W_s =[/tex] - 1.9924 kW + 213.1605 kW
[tex]W_s =[/tex] 211.1681 kW
[tex]W_s =[/tex] 283.181 hp
The power input is [tex]W_s =[/tex] 283.181 hp
A long conducting rod of rectangular cross section (20 mm 30 mm) and thermal conductivity k 20 W/m K experiences uniform heat generation at a rate q . 5 107 W/m3, while its surfaces are maintained at 300 K. Using a finite-difference method with a grid spacing of 5 mm, determine the temperature distribution in the rod.
Answer:
Explanation:
We are assuming that there is
a steady state two dimensional conduction
constant properties
uniform volumetric heat generation
From symmetry, we will be determining 6 unknown temperatures.
See attachment for calculation and and tabulation
With T(s) = 300 K, the set of equations were written directly into the IHT work space and solved for nodal temperatures.
The result is seen in the second attachment
If a sky diver decides to jump off a jet in Arkansas
with the intention of floating through Tennessee to
North Carolina, then completing his journey in a
likely manner back to Arkansas by drifting North
from his last point. What state would be the third t
be drifted over and what is the estimated distance
between the zone and then drop point?
Answer:
The answer to this question can be defined as follows:
Explanation:
The sky driver began his sky journey from Arkansas, drove across the Tennessee River then landed in North Carolina. He returned to both the north in the very same direction. He began with NC, traveled through Tennessee, eventually lands in Arkansas. But North Carolina has been in the third state on which skydiver was traveling over, and It's also more than 700 miles from Arkansas to the NC.
Trade-offs can be necessary at any point in time during the life cycle of a project. It is quite possible, and probable, for the criteria for the trade-offs to change over the life cycle of the project. Please also identifies how the relative importance of constraints of time, cost, and performance can change over the life cycle of the project.
Answer:
According to the Principles of Project management, the three factors which dominate the lifecycle of any project are:
Time;Cost; andPerformance.The relationship between the three is usually governed by trade-offs.
Explanation:
In simple term, in executing a project, one must deal with the factors mentioned above.
It is always desirous for a project to be finished within a stipulated time. If the time required is reduced inconsiderably, it will most likely incur more cost and even impact performance.
On the other hand, if the project is cost-sensitive and is executed to a very minimalistic budget, performance will be impacted and it may take a protracted amount of time.
In addition to the above, if the principal decides to change the original design of the project, the performance expected is altered. This will attract additional time as well as cost.
It is possible for any of the above factors to be renegotiated and readjusted at any time during the project. It usually is a trade-off.. that is one for the other.
Cheers!
A generator operating at 50 Hz delivers 1 pu power to an infinite bus through a transmission circuit in which resistance is ignored. A fault takes place reducing the maximum power transferable to 0.5 pu whereas before the fault, this power was 2.0 pu and after the clearance of the fault, it is 1.5 pu. Using equal area criterion, determine the critical clearing angle.
Answer:
critical clearing angle = 70.3°
Explanation:
Generator operating at = 50 Hz
power delivered = 1 pu
power transferable when there is a fault = 0.5 pu
power transferable before there is a fault = 2.0 pu
power transferable after fault clearance = 1.5 pu
using equal area criterion to determine the critical clearing angle
Attached is the power angle curve diagram and the remaining part of the solution.
The power angle curve is given as
= Pmax sinβ
therefore : 2sinβo = Pm
2sinβo = 1
sinβo = 0.5 pu
βo = [tex]sin^{-1} (0.5) = 30[/tex]⁰
also ; 1.5sinβ1 = 1
sinβ1 = 1/1.5
β1 = [tex]sin^{-1} (\frac{1}{1.5} )[/tex] = 41.81⁰
∴ βmax = 180 - 41.81 = 138.19⁰
attached is the remaining solution
The critical clearing angle = [tex]cos^{-1} 0.3372[/tex] ≈ 70.3⁰
The half-wave rectifier below is operating at a frequency of 60 Hz, and the rms value of the transformer output voltage is 6.3 V. (a) What is the value of the dc output voltage VO if the diode voltage drop is 1 V? (b) What is the minimum value of C required to maintain the ripple voltage to less than 0.25 V if R = 0.5Ω?
Given Information:
Frequency = f = 60 Hz
Transformer output voltage = Vrms = 6.3 V
Diode voltage drop = Vd = 1 V
Ripper voltage = Vr = 0.25 V
Load resistance = R = 0.5 Ω
Required Information:
a) dc output voltage = V₀ = ?
b) Capacitane = C = ?
Answer:
a) dc output voltage = V₀ = 2.52 V
b) Capacitane = C = 0.336 F
Explanation:
a) The average or dc output voltage of a half-wave rectifier is given by
[tex]V_0 = V_p/\pi[/tex]
Where Vp is given by
[tex]V_p = (V_{rms} \times \sqrt{2}) - V_d \\\\V_p = (6.3 \times \sqrt{2}) - 1 \\\\V_p = 8.91 - 1 \\\\V_p = 7.91 \: V \\\\[/tex]
So, the dc output voltage is
[tex]V_0 = 7.91/\pi \\\\V_0 = 2.52 \: V[/tex]
b) The minimum value of C required to maintain the ripple voltage to less than 0.25 V is given by
[tex]$ C = \frac{I}{Vr \cdot f} $[/tex]
Where I is current, Vr is the ripple voltage and f is the frequency
[tex]$ I = \frac{V_0}{R} $[/tex]
[tex]$ I = \frac{2.52}{0.5} $[/tex]
[tex]I = 5.04 \: A[/tex]
[tex]$ C = \frac{5.04}{0.25 \cdot 60} $[/tex]
[tex]C = 0.336 \: F[/tex]
Therefore, 0.336 F is the minimum value of capacitance required to maintain the ripple voltage to less than 0.25 V
Consider fully developed laminar flow in a circular pipe. If the viscosity of the fluid is reduced by half by heating while the flow rate is held constant, how will the pressure drop change
Answer:
The pressure drop across the pipe also reduces by half of its initial value if the viscosity of the fluid reduces by half of its original value.
Explanation:
For a fully developed laminar flow in a circular pipe, the flowrate (volumetric) is given by the Hagen-Poiseulle's equation.
Q = π(ΔPR⁴/8μL)
where Q = volumetric flowrate
ΔP = Pressure drop across the pipe
μ = fluid viscosity
L = pipe length
If all the other parameters are kept constant, the pressure drop across the circular pipe is directly proportional to the viscosity of the fluid flowing in the pipe
ΔP = μ(8QL/πR⁴)
ΔP = Kμ
K = (8QL/πR⁴) = constant (for this question)
ΔP = Kμ
K = (ΔP/μ)
So, if the viscosity is halved, the new viscosity (μ₁) will be half of the original viscosity (μ).
μ₁ = (μ/2)
The new pressure drop (ΔP₁) is then
ΔP₁ = Kμ₁ = K(μ/2)
Recall,
K = (ΔP/μ)
ΔP₁ = K(μ/2) = (ΔP/μ) × (μ/2) = (ΔP/2)
Hence, the pressure drop across the pipe also reduces by half of its initial value if the viscosity of the fluid reduces by half of its value.
Hope this Helps!!!
A 3-phase, 50 Hz, 110 KV overhead line has conductors placed in a horizontal plane 3 m apart. Conductor diameter is 2.5 cm. If the line length is 220 km, determine the charging current per phase assuming complete transposition. (6 Marks)
Answer:
A 3-phase, 50 Hz, 110 KV overhead line has conductors
Explanation:
hope it will helps you
The rectangular frame is composed of four perimeter two-force members and two cables AC and BD which are incapable of supporting compression. Determine the forces in all members due to the load L in position (a) and then in position (b). Forces are positive if in tension, negative if in compression.
Answer:
Your question is lacking some information attached is the missing part and the solution
A) AB = AD = BD = 0, BC = LC
AC = [tex]\frac{5L}{3}T, CD = \frac{4L}{3} C[/tex]
B) AB = AD = BC = BD = 0
AC = [tex]\frac{5L}{3} T, CD = \frac{4L}{3} C[/tex]
Explanation:
A) Forces in all members due to the load L in position A
assuming that BD goes slack from an inspection of Joint B
AB = 0 and BC = LC from Joint D, AD = 0 and CD = 4L/3 C
B) steps to arrive to the answer is attached below
AB = AD = BC = BD = 0
AC = [tex]\frac{5L}{3} T, CD = \frac{4L}{3}C[/tex]
A gold vault has 3 locks with a key for each lock. Key A is owned by the
manager whilst Key B and C are in the custody of the senior bank teller
and the trainee bank teller respectively. In order to open the vault door at
least two people must insert their keys into the assigned locks at the same
time. The trainee bank teller can only open the vault when the bank
manager is present in the opening.
i) Determine the truth table for such a digital locking system (4 marks)
ii) Derive and minimize the SOP expression for the digital locking system
Answer:
i) Truth Table:
A | B | C | O
0 | 0 | 0 | 0
0 | 0 | 1 | 0
0 | 1 | 0 | 0
0 | 1 | 1 | 0 (condition 2 not satisfied)
1 | 0 | 0 | 0
1 | 0 | 1 | 1 (both conditions satisfied)
1 | 1 | 0 | 1 (both conditions satisfied)
1 | 1 | 1 | 1 (both conditions satisfied)
ii) The minimized sum of products (SOP) expression is
O = AC + AB
Explanation:
We have three inputs A, B and C
Let O is the output.
We are given two conditions to open the vault door:
1. At least two people must insert their keys into the assigned locks at the same time.
2. The trainee bank teller (C) can only open the vault when the bank manager (A) is present in the opening.
i) Construct the Truth Table
A | B | C | O
0 | 0 | 0 | 0
0 | 0 | 1 | 0
0 | 1 | 0 | 0
0 | 1 | 1 | 0 (condition 2 not satisfied)
1 | 0 | 0 | 0
1 | 0 | 1 | 1 (both conditions satisfied)
1 | 1 | 0 | 1 (both conditions satisfied)
1 | 1 | 1 | 1 (both conditions satisfied)
ii) SOP Expression using Karnaugh-Map:
A 3 variable Karnaugh-map is attached.
The minimized sum of products (SOP) expression is
O = AC + AB
The orange pair corresponds to "AC" and the purple pair corresponds to "AB"
Bonus:
The above expression may be realized by using two AND gates and one OR gate.
Please refer to the attached logic circuit diagram.
For laminar flow over a hot flat plate, the local heat transfer coefficient decreases with distance because (select all that are correct
Answer:
hello the answer options are missing here are the options
A)The thickness of the heated region near the plate is increasing
B)The velocities near the plates are increasing
C)The fluid temperature near the plate are increasing
ANSWER : all of the above
Explanation:
Laminar flow is the flow of a type of fluid across the surface of an object following regular paths and it is unlike a turbulent flow which flows in irregular paths (encountering fluctuations)
For laminar flow over a hot flat plate, the local heat transfer coefficient decreases with distance because :
The thickness of the heated region near the plate is increasingThe velocities near the plates are increasingThe fluid temperature near the plate are increasingIn the fully developed region of flow in a circular pipe, does the velocity profile change in the flow direction?
Answer:
No, the velocity profile does not change in the flow direction.
Explanation:
In a fluid flow in a circular pipe, the boundary layer thickness increases in the direction of flow, until it reaches the center of the pipe, and fill the whole pipe. If the density, and other properties of the fluid does not change either by heating or cooling of the pipe, then the velocity profile downstream becomes fully developed, and constant, and does not change in the direction of flow.
A photograph of the NASA Apollo 16 Lunar Module (abbreviated by NASA as the LM is shown on the surface of the Moon. Such spacecraft made six Moon landings during 1,969 - 72. A simplified model for one of the four landing gear assemblies of the LM is shown. If the LM has 13,500 kg mass, and rests on the surface of the Moon where acceleration due to gravity is 1.82 m/s^2, determine the force supported by members AB, AC, and AD. Assume the weight of the LM is uniformly supported by all four landing gear assemblies, and neglect friction between the landing gear and the surface of the Moon. TAB =N TAC = TAD =N A ( 2.6, 2.6, -2.2 ) m B(1.5, 1.5, 0)m C(2,1,-1.2)m D(1,2,-1.2)m
Answer:
[tex]\mathbf{F_{AB} = 13785.06 N }[/tex]
[tex]\mathbf{F_{AC} = -5062.38 N }[/tex]
[tex]\mathbf{F_{AD} = -5062.38 N }[/tex]
Explanation:
From the given information:
Let calculate the position vector of AB, AC, and AD
To start with AB; in order to calculate the position vector of AB ; we have:
[tex]r_{AB}^{\to} = r _{OA}^{\to} - r_{OB}^{\to} \\ \\ r_{AB}^{\to} = (2.6 \ \hat i + 2.6 \ \hat j - 2.2 \ \hat k ) - ( 1.5 \ \hat i + \ 1. 5 \hat j ) \\ \\ r_{AB}^{\to} = ( 2.6 \ \hat i - 1.5 \ \hat i + 2.6 \ \hat j - 1.5 \ \hat j - 2.2 \ \hat k) \\ \\ r_{AB}^{\to} = (1.1 \ \hat i + 1.1 \ \hat j - 2.2 \ \hat k ) m[/tex]
To calculate the position vector of AC; we have:
[tex]r_{AC}^{\to} = r _{OA}^{\to} - r_{OC}^{\to} \\ \\ r_{AC}^{\to} = (2.6 \ \hat i + 2.6 \ \hat j - 2.2 \ \hat k ) - ( 2\ \hat i + \ \hat j - 1.2 \ \hat k) \\ \\ r_{AC}^{\to} = ( 2.6 \ \hat i - 2\ \hat i + 2.6 \ \hat j - \ \hat j - 2.2 \ \hat k + 1.2 \ \hat k) \\ \\ r_{AC}^{\to} = (0.6 \ \hat i + 1.6 \ \hat j - \ \hat k ) m[/tex]
To calculate the position vector of AD ; we have:
[tex]r_{AD}^{\to} = r _{OA}^{\to} - r_{OD}^{\to} \\ \\ r_{AC}^{\to} = (2.6 \ \hat i + 2.6 \ \hat j - 2.2 \ \hat k ) - ( \hat i + \ 2 \hat j - 1.2 \ \hat k) \\ \\ r_{AD}^{\to} = ( 2.6 \ \hat i - \hat i + 2.6 \ \hat j - 2 \ \hat j - 2.2 \ \hat k + 1.2 \ \hat k) \\ \\ r_{AD}^{\to} = (1.6 \ \hat i + 0.6 \ \hat j - \ \hat k ) m[/tex]
However; let's calculate the force in AB, AC and AD in their respective unit vector form;
To start with unit vector AB by using the following expression; we have:
[tex]F_{AB}^{\to} = F_{AB} \dfrac{ r _{AB}^{\to} }{|r_{AB}^{\to}} \\ \\ \\ F_{AB}^{\to} = F_{AB} \dfrac{(1.1 \ \hat i + 1.1 \ \hat j - 2.2 \ \hat k ) }{\sqrt{ (1.1)^2 + (1.1)^2 + (-2.2 )^2 }} \\ \\ \\ F_{AB}^{\to} = F_{AB} \dfrac{(1.1 \ \hat i + 1.1 \ \hat j - 2.2 \ \hat k ) }{ \sqrt{7.26}} \\ \\ \\ F_{AB}^{\to} = F_{AB} \dfrac{(1.1 \ \hat i + 1.1 \ \hat j - 2.2 \ \hat k ) }{ 2.6944} \\ \\ \\ F_{AB}^{\to} = F_{AB} (0.408 \ \hat i+ 0.408 \ \hat j - 0.8165 \ \hat k ) N\\[/tex]
The force AC in unit vector form is ;
[tex]F_{AC}^{\to} = F_{AC} \dfrac{ r _{AC}^{\to} }{|r_{AC}^{\to}} \\ \\ \\ F_{AC}^{\to} = F_{AC} \dfrac{(0.6 \ \hat i + 1.6 \ \hat j - \ \hat k ) }{\sqrt{ (0.6)^2 + (1.6)^2 + (-1 )^2 }} \\ \\ \\ F_{AC}^{\to} = F_{AC} \dfrac{(0.6 \ \hat i + 1.6 \ \hat j - \ \hat k ) }{ \sqrt{3.92}} \\ \\ \\ F_{AC}^{\to} = F_{AC} \dfrac{(0.6 \ \hat i + 1.6 \ \hat j - \ \hat k ) }{1.9798} \\ \\ \\ F_{AC}^{\to} = F_{AC} (0.303 \ \hat i+ 0.808 \ \hat j - 0.505 \ \hat k ) N\\[/tex]
The force AD in unit vector form is ;
[tex]F_{AD}^{\to} = F_{AD} \dfrac{ r _{AD}^{\to} }{|r_{AD}^{\to}|} \\ \\ \\ F_{AD}^{\to} = F_{AD} \dfrac{(1.6 \ \hat i + 0.6 \ \hat j - \ \hat k ) }{\sqrt{ (1.6)^2 + (0.6)^2 + (-1 )^2 }} \\ \\ \\ F_{AD}^{\to} = F_{AD} \dfrac{(1.6 \ \hat i + 0.6 \ \hat j - \ \hat k ) }{ \sqrt{3.92}} \\ \\ \\ F_{AD}^{\to} = F_{AD} \dfrac{(1.6 \ \hat i + 0.6 \ \hat j - \ \hat k ) }{1.9798} \\ \\ \\ F_{AD}^{\to} = F_{AD} (0.808 \ \hat i+ 0.303 \ \hat j - 0.505 \ \hat k ) N\\[/tex]
Similarly ; the weight of the lunar Module is:
W = mg
where;
mass = 13500 kg
acceleration due to gravity= 1.82 m/s²
W = 13500 × 1.82
W = 24,570 N
Also. we known that the load is shared by four landing gears; Thus, the vertical reaction force exerted by the ground on each landing gear can be expressed as:
[tex]R =\dfrac{W}{4}[/tex]
[tex]R =\dfrac{24,570}{4}[/tex]
R = 6142.5 N
Now; the reaction force at point A in unit vector form is :
[tex]R^{\to} = Rk^{\to} \\ \\ R^{\to} = (6142.5 \ k ^{\to}) \ N[/tex]
Using the force equilibrium at the meeting point of the coordinates at A.
[tex]\sum F^{\to} = 0[/tex]
[tex]F_{AB}^{\to} +F_{AC}^{\to} + F_{AD}^{\to} + R^{\to} =0[/tex]
[tex][F_{AB} (0.408 \ \hat i + 0.408 \ \hat j - 0.8165 \ \hat k ) N + F_{AC} (0.303 \ \hat i + 0.808 \ \hat j - 0.505 \ \hat k ) N + F_{AD} (0.808 \ \hat i + 0.303 \ \hat j - 0.505 \ \hat k) N + (6142.5 \ k^ \to ) ][/tex]
[tex]= [ ( 0.408 F_{AB} +0.303 F_{AC} + 0.808F_{AD}) \hat i + (0.408 F_{AB}+0.808F_{AC}+0.303F_{AD}) \hat j + (-0.8165 F_{AB} -0.505F_{AC} -0.505 F_{AD} +6142.5 ) k ^ \to ] = 0[/tex]
From above; we need to relate and equate each coefficients i.e i ,j, and [tex]k ^ \to[/tex] on both sides ; so, we can re-write that above as;
[tex]0.408 F_{AB} +0.303 F_{AC} + 0.808F_{AD}) =0 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ --- (1) \\ \\ 0.408 F_{AB}+0.808F_{AC}+0.303F_{AD}) =0 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ --- (2) \\ \\ -0.8165 F_{AB} -0.505F_{AC} -0.505 F_{AD} +6142.5 = 0 --- (3)[/tex]
Making rearrangement and solving by elimination method;
[tex]\mathbf{F_{AB} = 13785.06 N }[/tex]
[tex]\mathbf{F_{AC} = -5062.38 N }[/tex]
[tex]\mathbf{F_{AD} = -5062.38 N }[/tex]
The force vector of each member, depends on the magnitude of the
force and the unit vector of the member.
Responses:
The force supported by the members are;
Force supported by AB is; 13,799.95 NForce supported by AC is; -5070.2 NForce supported by AD is -5070.2 NHow can the unit vector of each member give their force?Resolving the given members into unit vectors gives;
[tex]\hat u_{AB} = \mathbf{\dfrac{(2.6 - 1.5) \cdot \hat i + (2.6 - 1.5)\cdot \hat j + (-2.2)\cdot \hat k }{\sqrt{(2.6- 1.5)^2 + (2.6 - 1.5)^2 + (-2.2)^2}}}[/tex][tex]\dfrac{(2.6 - 1.5) \cdot \hat i + (2.6 - 1.5)\cdot \hat j + (-2.2)\cdot \hat k }{\sqrt{(2.6- 1.5)^2 + (2.6 - 1.5)^2 + (-2.2)^2}}= 0.40825 \cdot \hat i + 0.40825\cdot \hat j - 0.81625\cdot \hat k[/tex]
[tex]\hat u_{AB} = \mathbf{0.40825 \cdot \hat i + 0.40825\cdot \hat j - 0.81625\cdot \hat k}[/tex]Similarly, we have;
[tex]\hat u_{AC} =\mathbf{ \dfrac{(2.6 - 2) \cdot \hat i + (2.6 - 1)\cdot \hat j + (-2.2+1.2)\cdot \hat k }{\sqrt{(2.6- 2)^2 + (2.6 - 1)^2 + (-2.2+1.2)^2}}}[/tex]
[tex]\dfrac{(2.6 - 2) \cdot \hat i + (2.6 - 1)\cdot \hat j + (-2.2+1.2)\cdot \hat k }{\sqrt{(2.6- 2)^2 + (2.6 - 1)^2 + (-2.2+1.2)^2}} =\dfrac{0.6\cdot \hat i +1.6\cdot \hat j -1\cdot \hat k }{\sqrt{0.6^2 + 1.6^2 + (-1.)^2}}[/tex]
[tex]\dfrac{0.6\cdot \hat i +1.6\cdot \hat j -1\cdot \hat k }{\sqrt{0.6^2 + 1.6^2 + (-1.)^2}}= 0.303046\cdot \hat i + 0.80812\cdot \hat j - 0.50508\cdot \hat k[/tex]
[tex]\hat u_{AC} =\mathbf{0.303046\cdot \hat i + 0.80812\cdot \hat j - 0.50508\cdot \hat k}[/tex][tex]\hat u_{AD} =\mathbf{ \dfrac{(2.6 - 1) \cdot \hat i + (2.6 -2)\cdot \hat j + (-2.2 + 1.2)\cdot \hat k }{\sqrt{(2.6-1)^2 + (2.6 -2))^2 + (-2.2 + 1.2)^2}}}[/tex]
[tex]\hat u_{AD} =\mathbf{0.80812\cdot \hat i+ 0.303046\cdot \hat j - 0.50508\cdot \hat k}[/tex]
The forces are therefore;
[tex]\vec F_{AB} =\mathbf{ F_{AB} \cdot \left ( 0.40825 \cdot \hat i + 0.40825\cdot \hat j - 0.81625\cdot \hat k \right)}[/tex]
[tex]\vec F_{AC} =\mathbf{ F_{AC} \cdot \left (0.303046\cdot \hat i + 0.80812\cdot \hat j - 0.50508\cdot \hat k\right)}[/tex]
[tex]\vec F_{AD} = \mathbf{F_{AD} \cdot \left (0.80812\cdot \hat i+ 0.303046\cdot \hat j - 0.50508\cdot \hat k\right)}[/tex]
[tex]Weight \ on \ the \ assembly = \dfrac{13,500 \, kg \times 1.82 \, m/s^2}{4} = 6,142.5 \, \hat k N[/tex]
Which gives;
[tex]\mathbf{0.40825 \cdot \hat i \cdot F_{AB}}[/tex] + [tex]0.303046\cdot \hat i \cdot F_{AC}[/tex] + [tex]0.80812\cdot \hat i \cdot F_{AD}[/tex] = 0
[tex]0.40825 \cdot \hat j \cdot F_{AB}[/tex] + [tex]0.80812\cdot \hat j \cdot F_{AC}[/tex] + [tex]0.303046 \cdot \hat j \cdot F_{AD}\left[/tex] = 0
[tex]-0.81625\cdot \hat k \cdot F_{AB}[/tex] - [tex]0.50508\cdot \hat k \cdot F_{AC}[/tex] - [tex]0.50508\cdot \hat k \cdot F_{AD}[/tex] + [tex]\mathbf{6,142.5 \, \hat k}[/tex] = 0
Which gives;
[tex]-0.81625\cdot \hat k \cdot F_{AB}[/tex] - [tex]0.50508\cdot \hat k \cdot F_{AC}[/tex] - [tex]0.50508\cdot \hat k \cdot F_{AD}[/tex] = [tex]-6,142.5 \, \hat k[/tex]
Solving gives;
[tex]F_{AB}[/tex] = 13799.95 N[tex]F_{AC}[/tex] = -5070.2 N[tex]F_{AD}[/tex] = -5070.2 NLearn more about unit vectors here:
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Water vapor at 10bar, 360°C enters a turbine operatingat steady state with a volumetric flow rate of 0.8m3/s and expandsadiabatically to an exit state of 1 bar, 160°C. Kinetic and potentialenergy effects are negligible. Determine for the turbine (a) the powerdeveloped, in kW, (b) the rate of entropy production, in kW/K, and (c)the isentropic turbine efficiency
Answer:
A) W' = 178.568 KW
B) ΔS = 2.6367 KW/k
C) η = 0.3
Explanation:
We are given;
Temperature at state 1;T1 = 360 °C
Temperature at state 2;T2 = 160 °C
Pressure at state 1;P1 = 10 bar
Pressure at State 2;P2 = 1 bar
Volumetric flow rate;V' = 0.8 m³/s
A) From table A-6 attached and by interpolation at temperature of 360°C and Pressure of 10 bar, we have;
Specific volume;v1 = 0.287322 m³/kg
Mass flow rate of water vapour at turbine is defined by the formula;
m' = V'/v1
So; m' = 0.8/0.287322
m' = 2.784 kg/s
Now, From table A-6 attached and by interpolation at state 1 with temperature of 360°C and Pressure of 10 bar, we have;
Specific enthalpy;h1 = 3179.46 KJ/kg
Now, From table A-6 attached and by interpolation at state 2 with temperature of 160°C and Pressure of 1 bar, we have;
Specific enthalpy;h2 = 3115.32 KJ/kg
Now, since stray heat transfer is neglected at turbine, we have;
-W' = m'[(h2 - h1) + ((V2)² - (V1)²)/2 + g(z2 - z1)]
Potential and kinetic energy can be neglected and so we have;
-W' = m'(h2 - h1)
Plugging in relevant values, the work of the turbine is;
W' = -2.784(3115.32 - 3179.46)
W' = 178.568 KW
B) Still From table A-6 attached and by interpolation at state 1 with temperature of 360°C and Pressure of 10 bar, we have;
Specific entropy: s1 = 7.3357 KJ/Kg.k
Still from table A-6 attached and by interpolation at state 2 with temperature of 160°C and Pressure of 1 bar, we have;
Specific entropy; s2 = 8.2828 KJ/kg.k
The amount of entropy produced is defined by;
ΔS = m'(s2 - s1)
ΔS = 2.784(8.2828 - 7.3357)
ΔS = 2.6367 KW/k
C) Still from table A-6 attached and by interpolation at state 2 with s2 = s2s = 8.2828 KJ/kg.k and Pressure of 1 bar, we have;
h2s = 2966.14 KJ/Kg
Energy equation for turbine at ideal process is defined as;
Q' - W' = m'[(h2 - h1) + ((V2)² - (V1)²)/2 + g(z2 - z1)]
Again, Potential and kinetic energy can be neglected and so we have;
-W' = m'(h2s - h1)
W' = -2.784(2966.14 - 3179.46)
W' = 593.88 KW
the isentropic turbine efficiency is defined as;
η = W_actual/W_ideal
η = 178.568/593.88 = 0.3
Suppose a student carrying a flu virus returns to an isolated college campus of 9000 students. Determine a differential equation governing the number of students x(t) who have contracted the flu if the rate at which the disease spreads is proportional to the number of interactions between students with the flu and students who have not yet contracted it. (Usek > 0for the constant of proportionality and x forx(t).)
Answer:
dx/dt = kx(9000-x) where k > 0
Explanation:
Number of students in the campus, n = 9000
Number of students who have contracted the flu = x(t) = x
Number of students who have bot yet contracted the flu = 9000 - x
Number of Interactions between those that have contracted the flu and those that are yet to contract it = x(9000 - x)
The rate of spread of the disease = dx/dt
Note: the rate at which the disease spread is proportional to the number of interactions between those that have contracted the flu and those that have not contracted it.
[tex]\frac{dx}{dt} \alpha [x(9000 -x)]\\[/tex]
Introducing a constant of proportionality, k:
dx/dt = kx(9000-x) where k > 0
Question 44
What should you do if you encounter a fishing boat while out in your vessel?
A
Make a large wake nearby.
B
Avoid making a large wake.
с
Pass on the side with the fishing lines.
D
Pass by close to the anglers.
Submit Answer
Answer:
The answer is B. Avoid making a large wake.
Explanation:
When passing a fishing boat it is important to maintain a minimal wake due to the dangers a large wake could pose to the fishing boat you are passing, it is part of maintaining safety on the water.
You can not pass on the sides with the fishing lines also, and you are supposed to communicate to the fishing boat before taking the appropriate action.
A student proposes a complex design for a steam power plant with a high efficiency. The power plant has several turbines, pumps, and feedwater heaters. Steam enters the first turbine at T1 (the highest temperature of the cycle) and saturated liquid exits the condenser at T7 (the lowest temperature of the cycle). The rate of heat transfer to the boiler (the only energy input to the system)is Qb. Determine the maximum possible efficiency and power output for this complex steam power plant design.
Answer:
Hello your question lacks some values here are the values
T1 = 500⁰c, T7 = 70⁰c, Qb = 240000 kj/s
answer : A) 56%
B) 134400 kw ≈ 134.4 Mw
Explanation:
Given values
T1 (tmax) = 500⁰c = 773 k
T7(tmin) = 70⁰c = 343 k
Qb = 240000 kj/s
A) Determine the maximum possible efficiency
[tex]n_{max}[/tex] = 1 - [tex]\frac{tmin}{tmax}[/tex] * 100
= 1 - ( 343 / 773 )
= 1 - 0.44 = 0.5562 * 100 ≈ 56%
B) Determine the power output for this complex steam power plant design
[tex]p_{out}[/tex] = Qb * max efficiency
= 240000 kj/s * 56%
= 240000 * 0.56 = 134400 kw ≈ 134.4 Mw
Technician A says that the micrometer operates on a simple principle: The spindle has 20 threads per inch, so one revolution of the thimble will advance or retract the spindle 1/20 of an inch. Technician B says that spindle has 50 threads per inch, so one revolution of the thimble will advance or retract the spindle 1/50 of an inch. Who is correct
Answer:
Explanation:
neither of the technicians is correct
How old are you? answer this question plz lol I will mark someone as brainliest
Answer:
100000000000000000000000
A steel alloy is known to contain 93.8 wt% Fe, 6.0 wt% Ni, and 0.2 wt% C. Assume that there are no alterations in the positions of other phase boundaries with the addition of Ni. (a) What is the approximate eutectoid temperature of this alloy
Answer:
650°C or 1,200°F
Explanation:
Data provided in the question
Steel alloy contains 93.8 wt% Fe, 6.0 wt% Ni, and 0.2 wt% C
Plus we also assume that there are no changes in the boundaries of postions who have other phases but there is an addition of Ni.
Based on the above information, the approximate eutectoid temperature of this alloy for 6.1 wt% is 650°C or 1,200°F
A thermal energy storage unit consists of a large rectangular channel, which is well insulated on its outer surface and encloses alternating layers of the storage material and the flow passage. Each layer of the storage material is an aluminum slab of width W=0.05 m, which is at an initial temperature of 25∘C25 ∘C. Consider conditions for which the storage unit is charged by passing a hot gas through the passages, with the gas temperature and the convection coefficient assumed to have constant values of T[infinity]=600∘CT [infinity]=600 ∘C and h=100W/m2⋅Kh=100W/m 2⋅K throughout the channel. How long will it take to achieve 75% of the maximum possible energy storage? What is the temperature of the aluminum at this time?
Answer:
the temperature of the aluminum at this time is 456.25° C
Explanation:
Given that:
width w of the aluminium slab = 0.05 m
the initial temperature [tex]T_1[/tex] = 25° C
[tex]T{\infty} =600^0C[/tex]
h = 100 W/m²
The properties of Aluminium at temperature of 600° C by considering the conditions for which the storage unit is charged; we have ;
density ρ = 2702 kg/m³
thermal conductivity k = 231 W/m.K
Specific heat c = 1033 J/Kg.K
Let's first find the Biot Number Bi which can be expressed by the equation:
[tex]Bi = \dfrac{hL_c}{k} \\ \\ Bi = \dfrac{h \dfrac{w}{2}}{k}[/tex]
[tex]Bi = \dfrac{hL_c}{k} \\ \\ Bi = \dfrac{100 \times \dfrac{0.05}{2}}{231}[/tex]
[tex]Bi = \dfrac{2.5}{231}[/tex]
Bi = 0.0108
The time constant value [tex]\tau_t[/tex] is :
[tex]\tau_t = \dfrac{pL_cc}{h} \\ \\ \tau_t = \dfrac{p \dfrac{w}{2}c}{h}[/tex]
[tex]\tau_t = \dfrac{2702* \dfrac{0.05}{2}*1033}{100}[/tex]
[tex]\tau_t = \dfrac{2702* 0.025*1033}{100}[/tex]
[tex]\tau_t = 697.79[/tex]
Considering Lumped capacitance analysis since value for Bi is less than 1
Then;
[tex]Q= (pVc)\theta_1 [1-e^{\dfrac {-t}{ \tau_1}}][/tex]
where;
[tex]Q = -\Delta E _{st}[/tex] which correlates with the change in the internal energy of the solid.
So;
[tex]Q= (pVc)\theta_1 [1-e^{\dfrac {-t}{ \tau_1}}]= -\Delta E _{st}[/tex]
The maximum value for the change in the internal energy of the solid is :
[tex](pVc)\theta_1 = -\Delta E _{st}max[/tex]
By equating the two previous equation together ; we have:
[tex]\dfrac{-\Delta E _{st}}{\Delta E _{st}{max}}= \dfrac{ (pVc)\theta_1 [1-e^{\dfrac {-t}{ \tau_1}}]} { (pVc)\theta_1}[/tex]
Similarly; we need to understand that the ratio of the energy storage to the maximum possible energy storage = 0.75
Thus;
[tex]0.75= [1-e^{\dfrac {-t}{ \tau_1}}]}[/tex]
So;
[tex]0.75= [1-e^{\dfrac {-t}{ 697.79}}]}[/tex]
[tex]1-0.75= [e^{\dfrac {-t}{ 697.79}}]}[/tex]
[tex]0.25 = e^{\dfrac {-t}{ 697.79}}[/tex]
[tex]In(0.25) = {\dfrac {-t}{ 697.79}}[/tex]
[tex]-1.386294361= \dfrac{-t}{697.79}[/tex]
t = 1.386294361 × 697.79
t = 967.34 s
Finally; the temperature of Aluminium is determined as follows;
[tex]\dfrac{T - T _{\infty}}{T_1-T_{\infty}}= e ^ {\dfrac{-t}{\tau_t}}[/tex]
[tex]\dfrac{T - 600}{25-600}= e ^ {\dfrac{-967.34}{697.79}[/tex]
[tex]\dfrac{T - 600}{25-600}= 0.25[/tex]
[tex]\dfrac{T - 600}{-575}= 0.25[/tex]
T - 600 = -575 × 0.25
T - 600 = -143.75
T = -143.75 + 600
T = 456.25° C
Hence; the temperature of the aluminum at this time is 456.25° C