How Is the Horizontal Distance Calculated When a Stone Drops on a Moving Log?

[eureka360]

hi guys.. could you please explain why 2.0x10^1 meters is the answer of the horizontal distance between the log and the bridge when the stone is dropped from rest from a 75-m-high bridge and lands on the log as it passess under the bridge if the log moves with a constant speed of 50 meters per second?

 

[gunblaze]

Are you sure the answer is 20 meters? Its either ur answer is wrong or that the log is travellin at a speed too fast in water!

 

[radou]

hi guys.. could you please explain why 2.0x10^1 meters is the answer of the horizontal distance between the log and the bridge when the stone is dropped from rest from a 75-m-high bridge and lands on the log as it passess under the bridge if the log moves with a constant speed of 50 meters per second?

Doesn't sound right. From the equation of the displacement of the stone $$y = 75 - \frac{1}{2}gt^2$$ you can obtain the time it takes to fall down, by setting y equal to zero and solving for t. Further on, use that time to obtain the distance of the log at the moment just before the stone is dropped.

 

[gunblaze]

well. The answer should be approximately 200 if the values given are correct. Or else, there may be some error in the question.

 

[radou]

well. The answer should be approximately 200 if the values given are correct. Or else, there may be some error in the question.

Yes, it's near 200 [m].

 

[eureka360]

the log is traveling 50 meters per second.. yeah i think its 200 meters..ok.. i got it.. thanks guys...