Two billiard balls, each with a mass of 0.17 kg, collide with each other on a pool table. Before the collision, one ball is moving south at 2.8 m/s and the
other ball is moving north at 1.6 m/s. What is the momentum of this system
after the collision?
A. 0.20 kg. m/s north
B. 0.20 kg m/s south
C. 0.60 kg m/s south
D. 0.60 kg: m/s north

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