We can solve the problem by using the first law of thermodynamics:

where
is the change in internal energy of the system
is the heat absorbed by the system
is the work done by the system on the surrounding
In this problem, the work done by the system is

with a negative sign because the work is done by the surrounding on the system, while the heat absorbed is

with a negative sign as well because it is released by the system.
Therefore, by using the initial equation, we find

Answer: A
Explanation: isotopes of the same thing element have the same number of protons in the nucleus but differ in the number of neutrons.
One problem with weight training as a way to improve overall health is that the results of a weight-training program are not measurable.
B.False
Answer:
A. More than 20% of your daily recommended amount.
Explanation:
Reading food labels can be tricky. The percent daily value listed on the right of all food labels lets you know what percent out of the recommended daily intake of each nutrient you are consuming in that specific food.
To check if the food you're consuming is a good source of that nutrient you need in higher amount, the nutrient must be labeled 20% or higher.
The rule used here is called the 5/20 rule. According to this rule, A nutrient that is 5% or below is considered less and a nutrient which is labeled 20% or higher is considered good enough in that food source.
Answer:
cold water strengthens the magnetic attractive force.
Explanation:
The molecules within the magnet will move slower because they have less kinetic energy,so there is less vibration within the magnets molecules.