Answer:
Option D 3.9
Explanation:
First, you need to use the correct equation which is the following:
COP = Q/W
Where:
Q = heat absorbed
W = work done by the pump
COP = coefficient of perfomance
We have all the data, so, all you need to do is replace in the above expression and you shoould get the correct result:
COP = 30 / 7.7
COP = 3.896
This result you can round it to 3.9. option D.
You do this one just like the other one that I just solved for you.
For this one ...
The density of the object is 2.5 gm/cm³.
We know that every cm³ of it we have contains 2.5 gm of mass.
We have to find out how many cm³ we have.
The question tells us: We have 2.0 cm³.
Each cm³ of space that the object occupies contains 2.5 gm of mass.
So the 2.0 cm³ that we have contains (2 x 2.5 gm) = 5 gms.
That's the mass of our object.
Answer:
<em>The frequency changes by a factor of 0.27.</em>
<em></em>
Explanation:
The frequency of an object with mass m attached to a spring is given as
= 
where is the frequency
k is the spring constant of the spring
m is the mass of the substance on the spring.
If the mass of the system is increased by 14 means the new frequency becomes
= 
simplifying, we have
= 
= 
if we divide this final frequency by the original frequency, we'll have
==> ÷
==> x 
==> 1/3.742 = <em>0.27</em>
Answer:
B. A car sits at rest at a stop sign.
Its momentum is (1000) x (its speed in m/s).
