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Grade 12Mechanics

A motorboat going downstream overcame a raft at a point A,t=60min later it turned back and passed the raft at a distance L=6.0km from the point A .Find the flow velocity assuming the duty of the engine to be constant.

Profile image of Vinay Arya
16 Years agoGrade 12
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1 Answer

Profile image of Ravi
11 Years ago
The flow velocity can be considered to be equal to the velocity of the raft. The point A at which the motorboat crossed the raft is the starting point. So, the motorboat with the velocity (vm+vf) moved till point B. After this, it turned around and started to move with the velocity (vm-vf) till it met with the raft which was moving with the velocity vfat a point 6 km from the starting point.

So, the raft moved for 60 min(=1hr) with velocity vfand covered 6 km.

Using this information, interpret in mathematical terms to form an eqn and simplify further to get the value of vfwhich will be the flow velocity.

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