How long would a 150 W lightbulb have to glow to produce the same amount of energy expended by Georgie? Answer in units of s.

Question

Georgie was pulling her brother (of mass 28 kg) in a 9.1 kg sled with a constant force of 23 N for one block (112 m). How much work did Georgie do? Answer in units J

I dont know how to do this

Answer 1

Lucas S.,

Since there is a stated force and no mention of friction or other opposing forces, 23N is the net horizontal force. Work done by this force in the horizontal direction is not affected by the weight which is vertically downwards.

so Work = Force x displacement

= 23•112 = 2576J

Now since power is energy/time

for the 150 watt bulb 150 = 2576/t

t = 2576/150 = 17.17s.

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Mr. A