Opportunity cost refers to what you have to give up to buy what you want in terms of other goods or services. When economists use the word “cost,” we usually mean opportunity cost.
Answer:
The system loses 90 kJ of heat
Explanation:
We can answer the question by using the 1st law of thermodynamics, which states that:

where
is the change in internal energy of the system
is the heat absorbed by the system (positive if absorbed, negative if released by the system)
is the work done by the system (positive if done by the system, negative if done by the surrounding on the system)
In this problem, we have:
is the work done (negative, because it is done by the surrounding on the system)
is the increase in internal energy
Using the equation above, we can find Q, the heat absorbed/released by the system:

And the negative sign means that the system has lost this heat.
Answer:
Time period, 
Explanation:
Given that,
The quartz crystal used in an electric watch vibrates with a frequency of 32,768 Hz, f = 32768 Hz
We need to find the period of the crystal's motion. The relationship between the frequency and the time period is given by :

T is the time period of the crystal's motion.
Time period is given by :

So, the time period of the crystal's motion is
. Hence, this is the required solution.
~Hello there! ^_^
Your question: A plant blossoms with violet-colored flowers. The flowers appear violet because they absorb all light rays except for____ rays.
Your answer: A plant blossoms with violet-colored flowers. The flowers appear violet because they absorb all light rays except for violet rays.
Hope this helps~
Explanation:
Light Light from a moving source travels at 300,000 km/sec (186,000 miles/sec).
Note:
The Speed of Light Is Constant.