- #1

- 27

- 0

I know that F=T-mg=ma=0

T=3500N

Work=3*165=495W=F/t

But I'm not really sure how to sort this problem out and incorporate the 75% efficiency of the pulley and the height above ground. Please help me.

- Thread starter xregina12
- Start date

- #1

- 27

- 0

I know that F=T-mg=ma=0

T=3500N

Work=3*165=495W=F/t

But I'm not really sure how to sort this problem out and incorporate the 75% efficiency of the pulley and the height above ground. Please help me.

- #2

- 12,116

- 153

Not quite. You are equating work (units: Joules) with power (units: Watts) here, but they are not the same. And neither of those would equal force/time.Work=3*165=495W=F/t

At any rate, 495W is the power exerted by the 3 people. So how much of that power gets transmitted to the piano? (hint: it is not 100% of the power)

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