A Top Fuel dragster accelerates uniformly from rest to a speed of 497.52 kph in a time of 4.96 seconds. How long does it take the car to reach 100 m/s?

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Answer 1 · 2015-08-22T22:43:43

$3.59 s$ $3.59"s"$

Use this equation of motion:

$v = u + a t$ $v=u+at$

We need to convert the final velocity into $m/s$ $"m/s"$ :

$497.52 km/hr = 497.52 \times 10^{3} m/hr$ $497.52"km/hr"=497.52xx10^3"m/hr"$

$= \frac{497.52 \times 10^{3}}{60 \times 60} = 138.2 m/s$ $=(497.52xx10^3)/(60xx60)=138.2"m/s"$

The acceleration is the rate of change of velocity with time which is:

$a = \frac{138.2 - 0}{4.96} = 27.86 m . s^{- 2}$ $a=(138.2-0)/(4.96)=27.86m.s^(-2)$

So:

$100 = 0 + 27.86 \times t$ $100=0+27.86xxt$

$t = \frac{100}{27.86} = 3.59 s$ $t=100/27.86=3.59"s"$