Work-Energy Theorem: in the Figure, a 900-Kg Crate Is on a Rough

Multiple Choice

Work-energy theorem: In the figure, a 900-kg crate is on a rough surface inclined at 30°. A constant external force is applied horizontally to the crate. While this force pushes the crate a distance of 3.0 m up the incline, its velocity changes from 1.2 m/s to 2.3 m/s. How much work does friction do during this process?

A) - 3700 J
B) - 7200 J
C) + 3700 J
D) + 7200 J
E) zero