Answer:
30 hours
15 hours.
Explanation:
Let the Kelly used sprinkler for t hours and Gracia used the sprinkler for the rest ie (45 - t) hours .
Water output by Kelly = (35 x t) L
Water output by Gracia = 20 ( 45 - t ) L
Total output = 35t + 20(45 - t)
So, 35 t + 20 (45 - t ) = 1350
35 t + 900 - 20 t = 1350
15 t = 450
t = 30 hours
So Kelly used sprinkler for 30 hours and Gracia used it for 45 - 30 = 15 hours.
When conducting a search to identify a text's credibility and reliability, you have to check the following characteristics:
- Sources: where the information is obtained and it is supposed to be true. It is said that you need at least three different sources that explain the same information for it to be validated.
- Is the article is current?: articles could change all the time, specially scientific ones because new discoveries can change what was discovered before, so it is important to check if the text you are reading is current or not, and if it is not, you need to check if something has changed during all those years.
<h3>Article's credibility</h3>
In this exercise, you have to present an article and describe the purpose of the source and if the article is current or not.
For example, let's select an article called "How using social media affects teenagers".
The purpose of the sources in this article is to demonstrate how social media affects teenagers using different surveys.
Check more information about sources here brainly.com/question/24708478
Answer: When 
Explanation:
According to first law of thermodynamics, energy can neither be created nor be destroyed. It can only be transformed from one form to another.
= change in enthalpy
P = pressure
= change in volume
=Change in internal energy
q = heat absorbed or released
w = work done on or by the system
Thus for ,
The heat evolved or absorbed by the system in a physical or chemical process, equal the change in enthalpy of the system when
Answer:
D) momentum of cannon + momentum of projectile= 0
Explanation:
The law of conservation of momentum states that the total momentum of an isolated system is constant.
In this case, the system cannon+projectile can be considered as isolated, because no external forces act on it (in fact, the surface is frictionless, so there is no friction acting on the cannon). Therefore, the total momentum of the two objects (cannon+projectile) must be equal before and after the firing:
But the initial momentum is zero, because at the beginning both the cannon and the projectile are at rest:
So the final momentum, which is sum of the momentum of the cannon and of the projectile, must also be zero:
I think the correct answer from the choices listed above is option D. Solar cells convert electromagnetic energy into electrical energy. This is because the photons from the rays of light are electromagnetic waves or particles. Hope this answers the question.
