Explanation:
A molecule can be made up from same or different elements. Whereas a compound will have different atoms.
Therefore, the difference between a molecule and a compound is that a compound is made up of atoms from different elements.
For example, 
is a molecule and NaCl is a compound.
And a chemical change creates a new substance.
Answer:
power is the rate at which energy is transferred or converted
the unit of power is Watts
Answer:
This has all the answer (Data sheet, graph, answers to the questions, and the summary) :)
Answer:
No, the sound produced by screeching brakes is not a useful form of energy, because it does not contribute to stopping the car.
The answer is d, gravity is the only force acting on the object
