A. <span>I .................
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Answer:
An external force is a force that acts on an object within the system from outside the system. This type of force is different than an internal force, which acts between two objects that are both within the system. The net external force combines these two definitions; it is the total combined external force
Explanation:
ig the answer is true
Answer:
The cup with 0.5L
Explanation:
To know what amount of water you take into account the specific heat of the water. The specific heat of water is:

Thus, 4186 J of energy are needed to icrease the temperature of 1 kg water in 1°C. Then, more grams of water will need more energy.
You have that one cup has 0.5 L and the other one has 750mL = 0.75L
The second cup of water will need more heat because the amount of water contained in the second cup is greater than in the first cup with 0.5L