Diego is trying to lift a piano to the second floor of his house. Diego uses a pulley system and gives a big lift to the piano.The piano moves upward, then stops, and then it starts to fall to the ground. (The direction of the force of gravity is negative.)

Question

Which list best describes the forces on the piano in the proper order?

positive force → balanced force → negative force
negative force → balanced force → positive force
positive force → unbalanced force → negative force
negative force → unbalanced force → positive force

Answer 1

To properly describe the forces acting on the piano in the scenario provided, we can analyze the different stages:

1. Positive Force: When Diego applies a force to lift the piano, this is a positive force acting upward.

2. Balanced Force: When the piano reaches its highest point and stops, the upward force (applied by the pulley system) is equal to the downward force of gravity. At this point, the forces are balanced, and the piano does not move.

3. Negative Force: Once Diego stops applying the force, the only force acting on the piano is gravity, which pulls it downward (negative force). It then falls.

Given this analysis, the best description of the forces on the piano in the proper order is:

positive force → balanced force → negative force.