Kevin used a pulley to lift a piano to the third floor of his apartment. His input work was 12,000 J and the output work was 10,000 J. What was the mechanical efficiency of the pulley? A . 50%
B. 83.3%
C . 120%
D. 16.7%

“when two plates carrying continents collide, the continental crust buckles and rocks pile up, creating towering mountain ranges. when an ocean plate collides with another ocean plate or with a plate carrying continents, one plate will bend and slide under the other. this process is called subduction. “ i found this on google i hope it