You should give answers since some people will just try and find any answer, which happened to me. So like if you have answers for the question just put them like A B C D kinda like true or false for others to know what they got instead of giving them more work, and then they just give you random answers.
Answer;
(3) Substance A is an element and substance Z is a compound.
Explanation;
-A compound is a substance formed when two or more chemical elements are chemically bonded together, such as water, carbon dioxide, methane, etc while an element is a pure chemical substance made of same type of atoms, such includes, oxygen, potassium, hydrogen, carbon, etc.
- Compounds can be broken
down or decomposed into simpler substances: elements cannot be broken down chemically into simpler substances .
we have
work done (W)= force(F) × displacemen(s)
or, 80= F× 8
or, F= 10 N
therefore, 10 N force is required to lift the rock.