Explanation
Power consumed by each device, P=500 W=0.50 kW
Time, t=10 h
Expression for the energy consumed is written as,
W=P×t
Step 2: Calculations,
Energy consumed by each device, W=0.50×10=5kWh
Energy consumed by four devices, =4×5=20 kWh
Gravitational Potential energy, W=mgh
h= vertical displacement =5 m
m= Mass of object =40 Kg
g= Acceleration due to gravity =9.8 ms−2
Kinetic Energy = Loss in PE= 40×5×9.8=1960 J
For half way down=19602=980 J
At this point i.e. half way object has an equal amount of potential and kinetic energy.
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