During a 400-m race, a runner crosses the 100 m mark with a velocity of 12 m/s. What would be her final position if she maintained her velocity for another 10 seconds (in m)?

Explanation:

Given that

Total race distance is 400m

Her initial velocity was 0m/s²

At the 100m mark, after she has travelled 100m, her final velocity was v=12m/s²

Using equation of motion

Let determine her constant acceleration

v²=u²+2as

12²=0²+2×a×100

144=0+200a

144=200a

a=144/200

a=0.72m/s²

Then we want to know her position after another 10second

So total time is 10+12=22seconds

Then, using equation of motion

Let determine his postion

S=ut+½at²

S=0•t+½×0.72×22²

S=0+174.24

S=174.24 m

Her position will be 174.24m

change tension

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