A building has an electric lift that carries a maximum load of each of average mass
PHYSICS · Subjective · CBSE · Physics · Work and Energy · Work and Energy
Problem
A building has an electric lift that carries a maximum load of 6passengers each of average mass 60kg. The lift cage itself has a mass of 240kg. The lift rises vertically through a height of 12m from the ground floor to the first floor.
(a) List all the masses that must be considered while calculating the gain in potential energy for one fully-loaded upward trip.
(b) Determine the total potential energy gained by the lift system in one such trip.
(c) The lift motor operates at 40% efficiency. Calculate the minimum electrical energy that must be supplied to make one upward trip with full load.
(d) If electrical energy costs Rs. 6 per kWh, find the cost of making 150 such trips in a day.