A 25 kg crate rests at the bottom of a 20° rough incline
PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Work Energy and Power · Work Energy and Power
Problem
A 25 kg crate rests at the bottom of a 20° rough incline. The coefficient of kinetic friction between the crate and the incline is 0.15. Starting from rest, the crate is pulled 10.0 m up the incline by a winch that exerts a constant 250 N force parallel to the surface.
(a) Derive an expression for, and then calculate numerically, the total change in the mechanical energy (gravitational potential energy plus kinetic energy) of the crate–Earth system during the 10.0 m pull.
(b) Determine the crate’s speed at the end of the 10.0 m displacement.
(c) Calculate the average power output of the winch during the pull.
(d) Determine the instantaneous power being delivered by the winch at the instant the crate reaches the end of the 10.0 m path, and compare it to the average power found in part (c).