I have solved this question several times and the answer turned to be wrong every time.
-A car speeds up uniformly from rest so that it has a velocity of 30m/s after 20s.
How long does it take to travel 250 m?
* putting in mind that the answer is 18 s.
So, I did like this, since it takes 20 s to travel 300 m in the velocity of 30m/s---> so, for travelling 250m it takes the car 16,6 s if we considered the same velocity.
+14915 A car speeds up uniformly from rest so that it has a velocity of 30m/s after 20s.
How long does it take to travel 250 m?
* putting in mind that the answer is 18 s.
\(b=\frac{v}{t}=\frac{30m}{20s^2}=1.5\ m/s^2\)
\(s=\frac{b}{2}t^2\)
\(t=\sqrt{\frac{2s}{b}}=\sqrt{\frac{2* 250\ m*s^2}{1.5m}}=18.257s\)
\(The \ car \ runs \ 18.257\ seconds.\)
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