Placing x-markers to drop water balloon on students

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Homework Help Overview

The problem involves determining the appropriate placement of an x-marker on the sidewalk for dropping water balloons from a height of 20 meters, considering the approach speed of students at 2 m/s.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the calculation of free-fall time and question the source of the acceleration value used in the problem. There is also a consideration of whether acceleration can be assumed to be zero due to constant walking velocity.

Discussion Status

The discussion is ongoing, with participants providing feedback on calculations and questioning assumptions. Some guidance has been offered regarding significant figures in the results.

Contextual Notes

There is a mention of confusion regarding units and the assumption of acceleration in the context of the problem, which may affect the calculations being discussed.

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Homework Statement



You and your roommate plot to drop water balloons on student entering your dorm. your window is 20m above the side walk. You plan is to place an x on the side walk to mark the spot a student must be when you drop the balloon. You note that most student approach the dorm at 2ms^-1. How far from the impact point do you place the x?

Homework Equations



None

The Attempt at a Solution



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The first half, where you computed the free falling time, is correct. The second half - where does 2 ms-2 come from?
 
voko said:
The first half, where you computed the free falling time, is correct. The second half - where does 2 ms-2 come from?

Opps. A slip in the label of unit which had me confuse velocity for acceleration. I'll redo it. Can I assume acceleration is 0ms^-2? I think I could since the walking velocity is constant, acceleration is zero.
 
xf - xi = 2ms^-1 (2.0192751098s) + 0.5(0ms^-2)(2.019275109s)^2 = 4.03855m
 
Good, but you have way too many "significant" figures.
 
voko said:
Good, but you have way too many "significant" figures.

rounded off to 4.03m
 

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