Barium cation has +2 charge and oxide anion has −2 charge
Answer: If it does not support the hypothesis, you may choose to change the hypothesis or write a new one based on what was learned during the experiment.
Hypothesize a new answer to the question and a new way to test it.
Explanation:
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.
I need a picture please befor i can answer
We can solve the problem by applying Newton's second law, which states that the resultant of the forces acting on an object is equal to the product between its mass and its acceleration:

We should consider two different directions: the direction perpendicular to the inclined plane and the direction parallel to it. Let's write the equations of the forces along the two directions, decomposing the weight of the object (mg):

(parallel direction) (1)

(perpendicular direction) (2)
where

is the angle of the inclined plane, N is the normal reaction of the plane,

is the frictional force, with

being the coefficient of friction.
From eq.(2), we find

and if we substitute into eq.(1), we can find the acceleration of the block:

from which