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Question
The US athlete Florence Griffith-Joyner won the 100 m sprint gold medal at Seoul Olympics in 1988, setting a new Olympic record of 10⋅54 s. Assume that she achieved her maximum speed in a very short time and then ran the race with that speed till she crossed the line. Take her mass to be 50 kg. Calculate the kinetic energy of Griffith-Joyner at her full speed.
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Solution
Given:
Distance covered by her, s = 100 m
Time taken by her to cover 100 m, t = 10.54 s
Mass, m = 50 kg
The motion can be assumed to be uniform.
\[\text{ Speed } , \nu = \frac{s}{t} = 9 . 487 \text{ m/s } \]
\[\text{ So, K . E } . = \frac{1}{2} {m\nu}^2 = 2250 J\]
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