Question

A lift is designed to carry a load of 4000kg through 10floors of a building averaging 6m per floor in 10sec calculate the horse power of the lift

Answer 1

height => 10 * 6 => 60m
mass => 4000kg and let g = 10m/s^2
therefore , force => mg => 4000*10=> 400000N
so work done => force * displacement
=> 40000*60 => 2400000J
time taken => 10 sec
therefore power => 2400000/10 => 240000W
therefore horse power => 240000/746
=> 321.7 J

Answer 2

Given,

The load carried by a lift through 10 floors = 4000 Kg

Height of each floor = 6 meters

Time taken by the lift = 10 sec

To find,

The horsepower of the lift.

Solution,

We can simply solve this numerical problem by using the following process:

Mathematically,

Power (P)

= Energy consumed/potential energy (E) ÷ Time (T)

= mass (m) × height (h) × acceleration due to gravity (g) / time taken (t)

{Statement-1}

Now, according to the question;

The horsepower of the lift

= mass (m) × height (h) × acceleration due to gravity (g) / time taken (t)

{according to statement-1}

= 4000 Kg × (6m × 10 floors) × 10 m/s^2 / 10 s

= 2,40,000 J/s

= (2,40,000×0.00134) hp

{Since 1 J = 0.0013 hp}

= 321.85 hp

Hence, the power of the lift is equal to 321.85 hp.