How much water remains unfrozen after 62.2 kJ is transferred as heat from 364 g of liquid water initially at its freezing point?
1 answer:
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Answer:
his is a multi-part question. Once an answer is submitted, you will be unable to return to this part. Air enters a nozzle steadily at 2.21 kg/m3 and 40 m/s and leaves at 0.762 kg/m3 and 192 m/s. The inlet area of the nozzle is 90 cm2.
determine (a) the mass flow rate through the nozzle, and (b) the exit area of the nozzle.
a)0.7956kg/s
b)5.437 × 10⁻³m²
Explanation:
The concepts related to the change of mass flow for both entry and exit is applied
The general formula is defined by
Where,
values are divided by inlet(1) and outlet(2) by
PART A) Applying the flow equation
PART B) For the exit area we need to arrange the equation in function of Area, that is
Answer:
The impact occured at a distance of 2478.585 meters from the person.
Explanation:
(After some research on web, we conclude that problem is not incomplete) The element "Part A" may lead to the false idea that question is incomplete. Correct form is presented below:
<em>A person, with his ear to the ground, sees a huge stone strike the concrete pavement. A moment later two sounds are heard from the impact: one travels in the air and the other in the concrete, and they are 6.4 seconds apart. How far away did the impact occur? (Sound speed in the air: 343 meters per second, sound speed in concrete: 3000 meters per second)</em>
Sound is a manifestation of mechanical waves, which needs a medium to propagate themselves. Depending on the material, sound will take more or less time to travel a given distance. From statement, we know this time difference between air and concrete (), in seconds:
(1)
Where:
- Time spent by the sound in concrete, in seconds.
- Time spent by the sound in the air, in seconds.
By suposing that sound travels the same distance and at constant speed in both materials, we have the following expression:
(2)
Where:
- Speed of the sound in concrete, in meters per second.
- Speed of the sound in the air, in meters per second.
- Distance traveled by the sound, in meters.
If we know that ,
and
, then the distance travelled by the sound is:
The impact occured at a distance of 2478.585 meters from the person.