A heat pump is a device used to heat something, in this case water. Heat pump takes heat from colder object and transfers it to warmer object. This is opposite to <span>direction of spontaneous heat transfer which from warmer to colder object.
In this problem a room got colder while water got warmer. This is due to work done by heat pump. This is what is described in correct answer c).
a) is not correct because it shows </span>direction of spontaneous heat transfer. It also says that <span>Aleksei’s family purchased a new water heater and in description givne in a) it would mean that water got colder.
b) is not correct because if the </span><span>burning fuel increased the thermal energy in the air it would mean that this room got warmer than rest of house.
d) is not correct because burning fuel does not absorb </span><span>thermal energy. It releases it.</span>
Answer:
Explanation:
To get the person Moving you have to overcome the static (means not moving) friction coefficient. U(static)
To get the person going at the same speed you have to overcome the kinetic friction coefficient. U(Kinetic)
Force to get him moving is 198 N. Force = ma = U(static)Mg
combining the 2 equations you get 198N = U(static)* 55kg *9.8m/s^2 Solve for U(static)
Same equation to keep him moving except with the dynamic force and the dynamic U
175N= U(kinetic)*55kg*9.8m/s^2 Solve (U dynamic)
Well, st first we should find <span>initial momentum for the first person represented in the task which definitely must be :
</span>
And then we find the final one :
Then equate them together :
So we can get the velocity, which is
In that way, according to the main rules of <span>conservation of momentum you can easily find the solution for the second person.
Regards!</span>
I think they can use more durable materials.
Correct answer choice is:
D. A frequency higher than the original frequency.
Explanation:
This is a true case of Doppler's effect. The Doppler effect can be defined as the effect originated by a traveling source of waves in which there is a visible higher variation in pulse for observers towards what the source is progressing and a visible descending shift in rate for observers from what the source is dropping.
