The Student Room Group
Uni students - Complete our survey >>
Uni students - Complete our survey >>
Uni students - Complete our survey >>

Motion Question - Waterfall

A stream provides a constantly acceleration of 6 ms^-2. A toy boat is pushed directly against the current and then released from a point 1.2m upstream from a small waterfall. Just before it reaches the waterfall, it is travelling at a speed of 5 m/s.

a) Calculate the initial velocity of the boat
b) Calculate the maximum distance upstream from the waterfall the boat reaches.

I have answered both questions correctly, now the only annoying thing is that when I read part B again, it really confuses me -

If the boat is being released 1.2m upstream from a waterfall, surely the maximum distance upstream would be 1.2m and not the answer that I got which was 2m? How can a boat go anymore upstream when the current will just push it downstream beneath the waterfall?

The maths behind it is relatively easy but the more I read into the question the more frustrated I get! Can someone explain with a diagram perhaps??
If the boat is released 1.2m from the edge with an initial velocity , then the boat will move further away from the waterfalls edge until the counterflow of the waterfall stops the motion away, and carries the boat with the current.

Original post by The-Spartan
If the boat is released 1.2m from the edge with an initial velocity , then the boat will move further away from the waterfalls edge until the counterflow of the waterfall stops the motion away, and carries the boat with the current.



Oh that makes sense.

I don't know why but something in my head just kept telling me that as soon as you stop pushing the boat would instantly go downstream rather than carry on upstream...
Original post by CrazyFool229
Oh that makes sense.

I don't know why but something in my head just kept telling me that as soon as you stop pushing the boat would instantly go downstream rather than carry on upstream...

Forgetting about the initial velocity always happens :biggrin: at least it will stick now :P

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you