Please show calculations on a separate page. 1. The world record in the 100 m da

Question

Please show calculations on a separate page.

1. The world record in the 100 m dash is 9.63 s, achieved by Usain Bolt at the 2012 London Olympic Games. (At the 2016 Rio de Janiero Olympics, his gold-winning time was 9.81 s.) It has been calculated that he did 29.5 kJ of work setting the world record. Bolt's mass at the event was 93.9 kg. What was his average power output in watts and in horsepower for the run? _____________ W _______________ hp

2. How much work can a 3.5 hp lawnmower do in 1 hr? (Hint: Convert hp to W.) ________________.

Explanation / Answer

1.

Power is given by:

Power = Workdone/time taken

Given that

Work-done = 29.5 kJ = 29500 J

time = 9.63 sec

So,

P = 29500/9.63

P = 3063.34 W

Now power in hp will be

1 hp = 745.7 W

Now,

P = 3063.34 W = 3063.34/745.7 = 4.11 hp

2.

Power = Workdone/time

time = 1 hr = 3600 sec

Power = 3.5 hp = 3.5*745.7 = 2609.95 W

So,

Work-done = 2609.95*3600 = 9395820 J

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