Solving for Cliff Height: An Alert Hiker's Task

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SUMMARY

The discussion centers on calculating the height of a cliff based on the time it takes for a boulder to fall the last third of the distance to the ground. The hiker observes that the boulder takes 1.3 seconds to fall this segment, leading to the application of the kinematic equation for vertical motion: y = yo + vit + 0.5gt². The initial velocity (Vi) is zero, and the final velocity (Vf) is zero at the point of impact. The problem also addresses the interpretation of extraneous solutions in the context of height calculations.

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  • Understanding of kinematic equations for vertical motion
  • Knowledge of gravitational acceleration (g = -9.8 m/s²)
  • Ability to interpret initial and final velocities in free fall
  • Familiarity with solving quadratic equations
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Homework Statement



An alert hiker sees a boulder fall from the top of a distant cliff and notes that it takes 1.3s for the boulder to fall the last 3rd of the way to the ground. Ignore air resistance.a) what is the height of the cliff in meters? b) If in part a) you get 2 solutions what does the extraneous one represent?

Homework Equations





The Attempt at a Solution



looking at the last 3rd
Vi = ?
Vf = 0 m/s
a = -9.8 m/s/s
t = 1.3s
x = ?

possibly going to use this equation: x = xo +vit +.5at^2 ?
 
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you should use the equation y = yo +vit +.5gt^2 for vertical motion.
also Vi should equal zero, as the boulder begins from rest in the y-axis and Vf should equal the final velocity as the boulder hits the ground
 

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