A. the change in medium cannot affect the angle if the angle is perpendicular.
We can solve the problem by using the first law of thermodynamics:

where

is the variation of internal energy of the system
Q is the heat absorbed by the system
W is the work done by the system
In this problem, the heat absorbed by the system is Q=+44 J, and the increase in internal energy is

. So we can rearrange the equation to calculate the work done:

and the work is positive, which means that it is done by the system on the surrounding.
A valid hypothesis must have test for proving the observation and is realistic, it considers the varibales it wants to measure. And it is tested either finding significance or not in the relationship between the studied variables.
<span>They utilize and make use of the scientific method in order to have clear basis and evidence for their investigations. Research method is always used to answer every scientific inquiry and in gaining evidential data or knowledge. The scientific method has the following process or at least undergoes the process of
1. Observation</span>
2. Hypothesis
3. Experimentation
4. Interpretation of data
5. Evaluating the data
6. Passing and recording the data
<span>These steps are crucial and the empirical data that these scientists obtain are very important to keep that is why research paper, thesis and dissertations exists.<span>
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