Question

An elevator motor moves a car with six people upward at a constant speed of 3.10 m/s. The mass of the elevator is 8.20 ✕ 102 kg, and the average mass of a person on the elevator is about 90.0 kg. Calculate the electric power that must be delivered to lift the elevator car, assuming half of the necessary power delivered goes into thermal energy.

Answer 1

Ours data:

$v= 3.1m/s$

$m_e=820Kg$

$m_p=90Kg$

We define the total weight

$m_{Total}=(820Kg+6*90)= 1360Kg$

So,

$P = F*v$

$P = mg*v$

$P = 1360*9.85*3.1$

$P = 41527.6 W$

However there is a lost in thermal energy, so

$P_{Total} = 2*41527.6W$

$P_{Total} = 83055.2 W = 83kW$