A hot brass plate is having its upper surface cooled by impinging jet of air at temperature of 15°C and convection heat transfer coefficient of 220 W/m^2•K. The 10-cm thick brass plate (rho = 8530 kg/m^3, cp = 380 J/kg•K, k = 110 W/m•K, and α = 33.9×10^–6 m^2/s) has a uniform initial temperature of 900°C, and the bottom surface of the plate is insulated. Required:
Determine the temperature at the center plane of the brass plate after 3 minutes of cooling.
Answers
Answer:
809.98°C
Explanation:
STEP ONE: The first step to take in order to solve this particular Question or problem is to find or determine the Biot value.
Biot value = (heat transfer coefficient × length) ÷ thermal conductivity.
Biot value = (220 × 0.1)÷ 110 = 0.2.
Biot value = 0.2.
STEP TWO: Determine the Fourier number. Since the Biot value is greater than 0.1. Tis can be done by making use of the formula below;
Fourier number = thermal diffusivity × time ÷ (length)^2.
Fourier number = (3 × 60 × 33.9 × 10^-6)/( 0.1)^2 = 0.6102.
STEP THREE: This is the last step for the question, here we will be calculating the temperature of the center plane of the brass plate after 3 minutes.
Thus, the temperature of the center plane of the brass plane after 3 minutes = (1.00705) (0.89199) (900- 15) + 15.
= > the temperature of the center plane of the brass plane after 3 minutes = 809.98°C.
Related Questions
A Coca Cola can with diameter 62 mm and wall thickness 300 um has an internal pressure of 100 kPa. Calculate the principal stresses at a point on the cylindrical surface of the can far from its ends.
Technician A says that the unitized structure of a hybrid vehicle is considerably different when compared to the same conventional model.Technician B says that hybrid vehicles have 12-volt and high voltage batteries.Who is right?
Suppose there is a mobile application that can run in two modes: Lazy or Eager. In Lazy Mode, the execution time is 3.333 seconds. In Eager Mode, the app utilizes a faster timer resolution for its computations, so the execution time in Eager Mode is 2 seconds (i.e., Eager Mode execution time is 60% of Lazy Mode execution time).After finishing computation, the app sends some data to the cloud, regardless of the mode it’s in. The data size sent to the cloud is 600 MB. The bandwidth of communication is 15 MBps for WiFi and 5 MBps for 4G. Assume that the communication radio is idle during the computation time. Assume that the communication radio for WiFi has a power consumption of 75 mW when active and 15 mW when idle. Similarly, assume that the communication radio for 4G has a power consumption of 190 mW when active and 25 mW when idle. The Idle Power of the CPU is 7 mW, whereas the Active Power of the CPU is 5 mW per unit utilization. Assume that the power consumption of the CPU is a linear function of its utilization. In other words: P = (Idle Power) + (Utilization)*(Power per unit Utilization). A configuration of the mobile app involves choosing a timer resolution (Lazy or Eager) and choosing a type of radio (WiFi or 4G). For example, faster timer resolution (Eager) and 4G network is a configuration, while slower resolution (Lazy) and WiFi is another. There are four possible configurations in all.Required:What is the average power consumption for Eager WiFi, Lazy WiFi, Eager 4G, and Lazy 4G?
(a) For a given material, would you expect the surface energy to be greater than, the same as, or less than the grain boundary energy? Why? (b) The grain boundary energy of a small-angle grain boundary is less than for a high-angle one. Why is this so?
Answers
Answer:
amount of electric charge transported = 1.13 × C
Explanation:
given data
electric current = 237.0 mA = 0.237 A
time = 8 min = 8 × 60 sec = 480 sec
solution
we get here amount of electric charge transported that is express as
amount of electric charge transported = electric current × time ...........1
put here value and we get
amount of electric charge transported = 0.237 × 480
amount of electric charge transported = 113.76 C
amount of electric charge transported = 1.13 × C
Answers
Answer:
Q=q
also
q=it
Explanation:
How to find magnitude of net electric charge when current flows through a capacitor with initial charge?
A capacitor is a device used in storing electric charges. The unit of capacitance is measured in farad
To find the magnitude of net electric charge in a capacitor, we use the following relation
Q=q
Q=the magnitude of net electric charge in coulombs
t=the time for an electron tpo pass through the capacitor
R=the resistance of the capacitor , measured in ohms
C=the capacitance of the capacitor measures in Farad
q=initial quantity of charge
Having all the parameters above will make it possible to determine the net electric charge
Recall also that
q=it
quantity (coulombs)=current*time(s)
What type of search do you think this would be?
Answers
This type of search would be a linear search. A linear search involves looking at each item in the array one by one until the desired item is found.
In this case, you would look at each square in the array until you find the one that matches the object pictured on the left. This is a common search method for small arrays or when the array is unsorted.
The algorithm continues until the target element is found, or until it reaches the end of the array and fails to find the target element. Linear searches are useful in scenarios where the array is small and unsorted, as the algorithm does not need to compare every element in the array to find the target element.
Learn more about linear search:
#SPJ11
Answers
The safety risks are the same for technicians who work on hybrid electric vehicles (HEVs) or EVs as those who work on conventional gasoline vehicles: False.
Safety risks can be defined as an assessment of the risks and occupational hazards associated with the use, operation or maintenance of an equipment or automobile vehicle that is capable of leading to the;
- Harm of a worker (technician).
- Injury of a worker (technician).
- Illness of a worker (technician).
- Death of a worker (technician).
Hybrid electric vehicles (HEVs) or EVs are typically designed and developed with parts or components that operates through the use of high voltageelectrical systems ranging from 100 Volts to 600 Volts. Also, these type of vehicles have an in-built HEV batteries which are typically encased in sealed shells so as to mitigate potential hazards to a technician.
On the other hand, conventional gasoline vehicles are typically designed and developed with parts or components that operates on hydrocarbon such as fuel and motor engine oil. Also, conventional gasoline vehicles do not require the use of high voltage electrical systems and as such poses less threat to technicians, which is in contrast with hybrid electric vehicles (HEVs) or EVs.
This ultimately implies that, the safety risks for technicians who work on hybrid electric vehicles (HEVs) or EVs are different from those who work on conventional gasoline vehicles due to high voltage electrical systems that are being used in the former.
In conclusion, technicians who work on hybrid electric vehicles (HEVs) or EVs are susceptible (vulnerable) to being electrocuted to death when safety risks are not properly adhered to unlike technicians working on conventional gasoline vehicles.
Find more information: brainly.com/question/2878752
Answer:
Batteries are safe when handled properly.
Explanation:
Just like the battery in your phone, the battery in some variant of an electric car is just as safe. If you puncture/smash just about any common kind of charged battery, it will combust. As long as you don't plan on doing anything extreme with the battery (or messing with high voltage) you should be fine.
Answers
Answer:
Explanation:
Given that
Load is uniformly distributed load and beam is simply supported.
Ra + Rb= wL
Ra = Rb =wL / 2
Lets x is measured from left side,then the deflection of beam at any distance x is given as
The maximum deflection of beam will at x = L/2 (mid point )
Answers
Answer:
Yield strength, tensile strength decreases with increasing temperature and modulus of elasticity decreases with increasing in temperature.
Explanation:
The modulus of elasticity of a material is theoretically a function of the shape of curve plotted between the potential energy stored in the material as it is loaded versus the inter atomic distance in the material. The temperature distrots the molecular structure of the metal and hence it has an effect on the modulus of elasticity of a material.
Mathematically we can write,
where,
E(t) is the modulus of elasticity at any temperature 'T'
is the modulus of elasticity at absolute zero.
is the mean melting point of the material
Hence we can see that with increasing temperature modulus of elasticity decreases.
In the case of yield strength and the tensile strength as we know that heating causes softening of a material thus we can physically conclude that in general the strength of the material decreases at elevated temperatures.