Answer:
ΔK = 24 joules.
Explanation:
Δ
Work done on the object
Work is equal to the dot product of force supplied and the displacement of the object.
* Δ
Δ
can be found by subtracting the vectors (7.0, -8.0) and (11.0, -5.0), which is written as Δ
= (11.0 - 7.0, -5.0 - -8.0) which equals (4.0, 3.0).
This gives us
*
=
=
J
Answer:
The average velocity has magnitude = 10 km/h , direction: east
Explanation:
In order to find the average velocity of the car we need to know the final and initial positions, and the time that took to get from one to the other.
Notice that since its movement was 60 km straight east and then from there 40 km straight west, the car is positioned at 20 km to the east of its initial departure point. therefore the vector change in position is a vector 20 km in magnitude, and direction towards the east.
Since it took the car a total of 1.33 hours plus 0.67 hours to reach its final position, the total time elapsed is: 1.33 + 0.67 hours = 2 hours.
Then,the velocity vector has magnitude; 20 km / 2 hours = 10 km/hour
As we mentioned above. the direction of the velocity vector is east.
Answer:
The mass rate of the cooling water required is: 
Explanation:
First, write the energy balance for the condensator: The energy that enters to the equipment is the same that goes out from it; consider that there is no heat transfer to the surroundings and kinetic and potential energy changes are despreciable.

Where w refers to the cooling water and s to the steam flow. Reorganizing,

Write the difference of enthalpy for water as Cp (Tout-Tin):

This equation will let us to calculate the mass rate required. Now, let's get the enthalpy and Cp data. The enthalpies can be read from the steam tables (I attach the tables I used). According to that,
and
can be calculated as:
.
The Cp of water at 25ºC (which is the expected average temperature for water) is: 4.176
. If the average temperature is actually different, it won't mean a considerable mistake. Also we know that
, so let's work with the limit case, which is
to calculate the minimum cooling water mass rate required (A higher one will give a lower temperature difference as a result). Finally, replace data:

Answer:
I think it is false. Johann balmer analyzed the spectral lines of hydrogen