Answer:
i) 25.04 W/m^2 .k
ii) 23.82 minutes = 1429.2 secs
Explanation:
Given data:
Diameter of steel ball = 15 cm
uniform temperature = 350°C
p = 8055 kg/m^3
Cp = 480 J/kg.k
surface temp of ball drops to 250°C
average surface temperature = ( 350 + 250 ) / 2 = 300°C
<u>i) Determine the average convection heat transfer coefficient during the cooling process</u>
<em>Note : Obtain the properties of air at 1 atm at average film temp of 30°C from the table " properties of air " contained in your textbook</em>
average convection heat transfer coefficient = 25.04 W/m^2 .k
<u>ii) Determine how long this process has taken </u>
Time taken by the process = 23.82 minutes = 1429.2 seconds
Δt = Qtotal / Qavg = 683232 / 477.92 = 1429.59 secs
attached below is the detailed solution of the given question
B. If you do 39-3/4 divided by 12-1/2 you get 3.18
Answer:
giving advertising to the governor with the state
Given:
size of scale model = 4(size of pump)
power ratio of pump and scale model = 5:1
Solution:
Let the diameter of scale model and pump be
and
respectively
and head be
and
respectively
Now, power, P is given as a function of head(H) and dischagre(Q)
P =
(1)
From eqn (1):

and

So,

Therefore,
= 
= 
= 
= 
= 
Answer:112.376 s
Explanation:
Given






Using Newton's law of cooling
=
=
7=
Taking log both side
t=112.376sec