A sprinter in a 100m race accelerates uniformly for the first 35m & then runs with constant velocity. If the sprinter's time for first 35m is 5.4 sec, determine his time for the race.

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written 8.4 years ago by

teamques10 ★ 68k

• modified 4.5 years ago

engineering mechanics

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written 8.4 years ago by

teamques10 ★ 68k

Given: $s=100m $

$s1=35m$ (distance covered with uniform acceleration)

$s2=65m $(distance covered with uniform velocity)

Applying, $s=ut + 0.5at2 \\ 35= 0 + 0.5 a(5.4)2 \\ a= 2.4 m/s2 $

Applying, $v= u+at \\ v = 2.4*5.4 = 12.96 m/s $

Now, time required to cover $65m$ with uniform velocity $12.96$ will be

$t = 65/12.96 = 5.015 sec $

Total time $= 10.415 sec $

Sprinter's time for race is $10.415 sec$

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