1600 Kg how many joule

Question

 

A mass of 1600 kg is lifted by a winch through a height of 25

meters (m) in 30 seconds.

Calculate (1) the work done

(2) if the efficiency of the winch is 60% find the

input power in kW.

(3) the energy consumed in kWh

Answer 1

1600kg has weight (force) of 1600×9.81=15696 Newtons.

(1) Work done=15696×25=392400 joules (force times distance).

(2) Efficiency=output/input=0.6. The output in this case is the work done from (1) (the winch must be capable of lifting the weight). This means that the input has to be higher to compensate for the loss of power because of friction, etc. So input=392400/0.6=654000 joules.

(3) kW=J/(1000t) where J is the work done in joules and t the time in seconds, so kW=654000/30000=21.8kW. The power is this multiplied by t as a fraction of an hour: 30/3600=0.1817kWh approx. Note that joules can be converted directly into kWh by dividing by 1000: 654 kWh.