Explanation:
When there is no change in chemical composition of a substance then it is known as physical change.
When we say that mass is conserved during a physical change then it means that total mass of the substance or object will remain the same from beginning till the end.
For example, a metal box of mass 20 grams is beaten with hammer. Its shape will change which is a physical change and after beaten with the hammer its mass still remains 20 grams.
Well if the rock doesn't move, then there is no amount of work done. There is no work done on an object if a force is applied to the object but it DOES NOT change its position, in this case is the rock.
Answer:

Explanation:
Time can be found by dividing the distance by the speed.

The distance is 45 meters and the speed is 12.5 meters per second.


Divide. Note that the meters, or "m" will cancel each other out.


It will take the dolphin 3.6 seconds to swim a distance of 45 meters are 12.5 meters per second.
This is known as Muscular Endurance.
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If the trend changed toward traditional (pre-World War II) families, the women’s rights are employment in manufacturing sector.
<h3>What is World war?</h3>
The war between two countries to take over each other's kingdom using weapons to kill each other.
Before the world war, the army needs armor, weapons, guns and tanks. Their manufacturing is only possible with many workers to work for long hours. If the men are not enough, then women are given opportunities to work with them.
Thus, the women’s rights are employment in manufacturing sector when trend changed traditional families.
Learn more about world war.
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