Answer:
PE = mgh
Explanation:
m is mass, g is gravitational constant (9.81) and h is height
Answer:
Mass of natural gas needed to heat the room is 350,000BTUs
Explanation:
The heating efficiency of a furnace is never 100% because not all energy is released and not all heat is available to heat the place. A lesser efficiency requires more consumption of fuel. Heating values are used for heating fuels in order to calculate the mass of fuel needed.
The heating value of natural gas is 1,000,000BTUs
Therefore the formular for calculating mass of natural gas needed= Heating value of natural gas×efficiency.
Mass=1,000,000×0.35
Mass=350,000BTUs
Answer:

Explanation:
Since, Alex is at rest. Therefore, the speed measured by him will be the absolute speed of car P. Therefore, taking easterly direction as positive:
And the absolute velocity of Barbara's Car is given as:
Now, for the velocity of Car p with respect to the velocity of Barbara's Car can be given s follows:


Answer:
The correct answer is option b. At higher elevations, it would take longer to hard boil an egg, because there is a lower boiling.
Explanation:
When we boil water at a very high temperature, it turns out that the water boils much faster. This is because the higher we are, <u>there will be less oxygen and less pressure in the atmosphere</u>. This implies that the water vapor becomes steam much faster than as it happens at low temperatures, so less heat will be needed for the water to boil.
That is why <u>if we want to cook an egg, we will have to lower the heat</u> of the kitchen when we put it on the fire, in order to avoid boiling water very quickly. Lowering the heat, <u>then cooking the egg will take much longer.
</u>
Given this data, the correct answer is option B, At higher elevations, it would take longer to hard boil an egg, because there is a lower boiling.