Complete Question
Air at 40C flows over a 2 m long flat plate with a free stream velocity of 7m/s. Assume the width of the plate (into the paper) is 0.5 m. If the plate is at a co temperature of 100C,find:
The total heat transfer rate from the plate to the air
Answer:
Explanation:
From the question we are told that:
Air Temperature 
Length 
Velocity 
Width 
Constant temperature 
Generally the equation for Total heat Transfer is mathematically given by
Where
h=Convective heat transfer coefficient
Therefore
Answer:
a) 1253 kJ
b) 714 kJ
c) 946 C
Explanation:
The thermal efficiency is given by this equation
η = L/Q1
Where
η: thermal efficiency
L: useful work
Q1: heat taken from the heat source
Rearranging:
Q1 = L/η
Replacing
Q1 = 539 / 0.43 = 1253 kJ
The first law of thermodynamics states that:
Q = L + ΔU
For a machine working in cycles ΔU is zero between homologous parts of the cycle.
Also we must remember that we count heat entering the system as positiv and heat leaving as negative.
We split the heat on the part that enters and the part that leaves.
Q1 + Q2 = L + 0
Q2 = L - Q1
Q2 = 539 - 1253 = -714 kJ
TO calculate a temperature for the heat sink we must consider this cycle as a Carnot cycle. Then we can use the thermal efficiency equation for the Carnot cycle, this one uses temperatures:
η = 1 - T2/T1
T2/T1 = 1 - η
T2 = (1 - η) * T1
The temperatures must be given in absolute scale (1453 C = 1180 K)
T2 = (1 - 0.43) * 1180 = 673 K
673 K = 946 C
The number of hours that will be needed to charge a 600mah battery will be 1.5 hours.
<h3>
What is a battery?</h3>
It should be noted that an electric battery simply means a source of electric power that consist of one or more electrochemical cells that are with external connections that are important for powering electrical devices.
It should be noted that when a battery is supplying power, then the positive terminal is the cathode while the negative terminal is the anode.
In conclusion, the number of hours that will be needed to charge a 600mah battery will be 1.5 hours.
Learn more about battery on:
brainly.com/question/16896465
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It’s in Wolfsburg Germany
Answer:
The answer is below
Explanation:
Given that:
Diameter (D) = 0.03 mm = 0.00003 m, length (L) = 2.4 mm = 0.0024 m, longitudinal tensile strength 
, Fracture strength
a) The critical length (
) is given by:
The critical length (4.5 mm) is greater than the given length, hence th composite can be produced.
b) The volume fraction (Vf) is gotten from the formula:
