A racing motor boat speeds up in a straight line in a lake, from rest. Referring to the acceleration-displacement graph for the speeding boat dind its speed when it passes a raft at a distance of `40m` from the starting poingt.
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Explanation

`v=sqrt (v_(0)^(2)+2(A))`
where, `A=(1)/(2) xx40 xx1=20`
and `v_(0)=0`
This gives `v=sqrt 40 ms^(-1)`
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