Consider an opaque horizontal plate that is well insulated on its back side. The irradiation on the plate is 2500 W/m2, of which
500 W/m2 is reflected. The plate is at 227°C and has an emissive power of 1200 W/m2. Air at 127°C flows over the plate with a convection heat transfer coefficient of 15 W/m2 ⋅ K. Determine the emissivity, absorptivity, and radiosity of the plate. What is the net heat transfer rate per unit area?
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Answer:
5.5g of ice melts when a 50g chunk of iron at 80°C is dropped into a cavity
Explanation:
The concept to solve this problem is given by Energy Transferred, the equation is given by,
Where,
Q= Energy transferred
m = mass of water
c = specific heat capacity
Temperature change (K or °C)
Replacing the values where mass is 50g and temperature is 80°C to 0°C we have,
Then we can calculate the heat absorbed by m grams of ice at 0°C, then
How Q_1=Q_2, so
Then 5.5g of ice melts when a 50g chunk of iron at 80°C is dropped into a cavity
If we want the object to continue to move at constant speed, it means that the resultant of the forces acting on the object must be zero. So far, we have:
- force F1 with direction north, of 10 N
- force F2 with direction west, of 10 N
The third force must balance them, in order to have a net force of zero on the object.
The resultant of the two forces F1 and F2 is
with direction at
north-west. This means that F3 must be equal and opposite to this force: so, F3 must have magnitude 14.1 N and its direction should be 
south-east.
- force F1 with direction north, of 10 N
- force F2 with direction west, of 10 N
The third force must balance them, in order to have a net force of zero on the object.
The resultant of the two forces F1 and F2 is
with direction at