Question

The power input into the food processor is 1150W. The power of the spinning blade is 900W. Calculate how much energy is wasted when the food processor is used for two minutes. show clearly how you get to your answer and give the unit.
(power=energy transferred/time taken.)

energy=

Answer 1

1 watt means 1 joule of energy per second

The food processor uses  1,150 joules of energy per second.
The blade uses 950 joules per second to slice, dice, and puree.

The rest of the energy goes to heat the appliance's motor, or
overcome friction in the blade's bearings, etc.  How much energy
does NOT go into slicing and pureeing ?

(1,150 watts) - (950 watts) = 200 joules per second

1 minute = 60 seconds
2 minutes = 120 seconds

Energy wasted in 2 minutes =

           (200 joules/second) x (120 seconds)  =  24,000 joules

That's enough energy to operate a 34-watt CFL (curly) light bulb
for 11 minutes  46 seconds.