Question

An engine pumps up $1000kg$ of coal from a mine $100m$ deep in $50sec$. The pumps is running with diesel and efficiency of diesel engine is $25$. Then its power consumption will be $(g=10m/se{c}^2)$:

• A. 10 kW
• B. 80 kW
• C. 20 kW
• D. 24 kW

Answer 1

The correct option is B 80 kW

Given, $Mass=1000kg,h=100m,t=50s,Effeciency=25\%$

Output power $=\frac{mgh}{t}$

$=1000kg\times 10m/s²\times \frac{100m}{50s}$

$=2\times {10}^{4}Watt=20kW$

Now, The Effeciency is equal to the Output power is divided by the Input power and multiplied by $100$

$25=\left[\frac{20kW}{(Input-power)}\right]\times 100$

Input power $=80kW$

Power of engine is $80kW$