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.

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

A. positive force → balanced force → negative force
B. negative force → balanced force → positive force
C. positive force → unbalanced force → negative force
D. negative force → unbalanced force → positive force

A. Positive force --> Balanced Force --> Negative Force

Explanation:

When the piano is moving upward it experiences a positive force. This force is acting upwards.

When the piano is stopped and not moving, the net forces on it are 0. This means that the upwards and downwards forces are balanced. Thus it is experiencing a balanced force.

When the piano is falling to the ground, it is experiencing a negative force. This force is aimed downward.

its A

Explanation:

waves moving from a fast medium to a slow medium will experience a reflection as light travels more slowly than red light. total internal reflection occurs when the critical angle is.