<u>Answer:</u>
<em>The initial distance between the trains is 1450 m.
</em>
<u>Explanation:</u>
In the question two trains are of equal length 400 m and moves at a uniform speed of 72 km/h. train A is moving ahead of train B. If the train B has to overtake train A it should accelerate.
Train B’s acceleration is 
and it accelerated for 50 seconds.
<em>
</em>
<em>t=50 s
</em>
<em>initial speed u=72km/h
</em>
<em>we have to convert this speed into m/s </em>
<em>
</em>
<em>Distance covered in accelerating phase 
</em>
<em>
</em>
<em>
</em>
If a train is just behind another, the distance covered by the train located behind during overtaking phase will be equal to the sum of the lengths of the trains.
<em>Here length of train A+length of train 
</em>
<em>Hence the initial distance between the trains = 
</em>
Answer:
A,B,D,E are wrong
(A) Heat exchangers are devices where two moving fluid streams are mixed together (B) Heat exchangers are devices where two moving fluid streams exchange mass (D) Heat exchangers are devices where two moving fluid streams exchange mechanical work without mixing together (E) There is no heat transfer between the two fluids of an insulated heat exchanger
Explanation:
A heat exchanger can be regarded as a system that bring about transfer heat between two or more than two fluids. It can function in cooling process and heating processes, the fluids involves in this process can have a solid wall to separate them so as to prevent mixing, direct contact could also be utilized. The mechanism is making hot gas jets which could fire upward over a glowing water that is passing through pipes, as water moves along the pipe, heat energy is been absorbed and there is heating up i.e heat is transferred. One is cooked the other is heated up. It is very essential to insulate the whole steam system along with heat exchangers so that energy could be saved and the temperature of the surface would be at safe-to-touch range and also steam quality could be maintained. The types of heat exchanger we have are;
✓Shell and tube heat exchangers.
✓Condensers, evaporators, and boilers
✓Double pipe heat exchangers.
✓Plate heat exchangers.
It should be noted Heat exchangers are devices where two moving fluid streams exchange heat (thermal energy) without mixing together
Answer:
As the pressure inside the pressure cooker increases as it is heated, the temperature also increases.
Explanation:
A pressure cooker contains water and steam in equilibrium at a pressure greater than atmospheric pressure.
According to the ideal gas law, as the pressure increases, the temperature also increases.
As the pressure inside the pressure cooker increases as it is heated, the temperature also increases.
Answer:
No change in the specific heat.
Explanation:
Specific heat is an intrinsic property that it has not depend upon on the amount of substance or energy added, it depends upon the material.
So, when twice the amount of energy is transferred, specific heat of the material does not change rather the energy that is twice in the amount to 1 kg of that material cause it to warm 2.0° C.
