Answer :
The work (newton-metres) the dock worker have to exert to lift the boat to 5 m in air is 6506.85 Nm
What is work done?
This is simply defined as the product of force and distance moved in the direction of the force. Mathematically, it can be expressed as
Workdone (Wd) = force (F) × distance (d)
Wd = Fd
How to determine the output work done
- Force (F) = 950 N
- Distance (d) = 5 m
- Output work =?
Output work = Fd
Output work = 950 × 5
Output work = 4750 Nm
How to determine the input work done
- Output work = 4750 Nm
- Efficiency = 73%
- Input work =?
Efficiency = (output / input) × 100
73% = 4750 / input
0.73 = 4750 / input
Cross multiply
0.73 × input = 4750
Divide both side by 0.73
Input work = 4750 / 0.73
Input work = 6506.85 Nm
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