The Answer is A becuase the piano moving up is is going in a positive way whe it stops the forces are equal then when it falls the forces are negative
Answer:
hello your question is incomplete attached below is the complete question
answer : 
Explanation:
The explanation behind the reasoning is attached below
Ranking the magnitude of the net electric force on the lower-left particle from the greatest to the least
Observations and Data are FACTS. Scientists use observations and data to draw a conclusion. Observations lead to the recording of data. Scientists ask questions about their observations and then collect data to answer their questions, then they have their evidence. Opinions are not facts, they are simply beliefs or value judgements. Then the scientist should repeat the experiment the results from different scientists should be similar- if the results are not similar and consistent then the experiment must be done again.
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The spring balance provides a mass measurement
