Answer:
Between 35°– 45°
Explanation:
In the vertical position, Point the flame in the direction of travel. Keep the flame tip at the correct height above the base metal. An angle of 35°–45° should be maintained between the torch tip and the base metal. This angle may be varied up or down to heat or cool the weld pool if it is too narrow or too wide
Answer:

Explanation:
The adiabatic throttling process is modelled after the First Law of Thermodynamics:


Properties of water at inlet and outlet are obtained from steam tables:
State 1 - Inlet (Liquid-Vapor Mixture)





State 2 - Outlet (Superheated Vapor)




The change of entropy of the steam is derived of the Second Law of Thermodynamics:


Answer:
Absolute pressure=70.72 KPa
Explanation:
Given that Vacuum gauge pressure= 30 KPa
Barometer reading =755 mm Hg
We know that barometer always reads atmospheric pressure at given situation.So atmospheric pressure is equal to 755 mm Hg.
We know that P= ρ g h
Density of 
So P=13600 x 9.81 x 0.755
P=100.72 KPa
We know that
Absolute pressure=atmospheric pressure + gauge pressure
But here given that 30 KPa is a Vacuum pressure ,so we will take it as negative.
Absolute pressure=atmospheric pressure + gauge pressure
Absolute pressure=100.72 - 30 KPa
So
Absolute pressure=70.72 KPa