To use the principle of work and energy to determine characteristics of a mass being pulled up an incline and determine the power that must be supplied to the system when the efficiency of the input system is considered.
As shown, a 56kg crate is pulled up a theta = 65 degree incline by a pulley and motor system. Initially at rest, the crate is pulled s = 4.5m up along the incline. Undergoing constant acceleration, the crate reaches a speed of 2.7m/s at the instant it has traveled this distance.
Part A - Power supplied to the crate when friction is considered
Considering the coefficient of kinetic friction μk = 0.15, determine the power that the motor must supply to the crate the instant the crate travels a distance of 4.5m.
Part B - Power supplied to the motor when efficiency is considered
If the motor has an efficiency of E = 0.87, what power must be supplied to the motor to raise the crate?