A and c
Because it defines the boundaries of the system
Answer:
maybe its heat sorry if it's wrong
because if friction is not in the problem so we are making heat or thermal energy
Explanation:
The left side of the periodic table has elements that have less number of electrons in the valence shell.
These elements loose electrons easily.These elements appear as metals or metalloids in nature.These are hard solids.Their inter molecular forces are very strong.
The right side of the periodic table has elements that have more number of electrons in the valence shell.
These elements gain electrons easily.These elements appear as non metals most of which are gases.Their inter molecular forces are weak.
Answer:
That is, mechanical waves cannot travel through a vacuum. This feature of mechanical waves is often demonstrated in a Physics class. A ringing bell is placed in a jar and air inside the jar is evacuated. Once air is removed from the jar, the sound of the ringing bell can no longer be heard.
