Free fall acceleration (time elapsed, initial & final speed)

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SUMMARY

The discussion focuses on a physics problem involving free fall acceleration, where a rock climber throws two stones from a 50-meter cliff. The first stone, with an initial speed of 2.0 m/s, takes 2.98 seconds to hit the water. Consequently, the second stone, thrown 1 second later, also hits the water at the same time, meaning it takes 1.98 seconds to reach the water. The calculations utilize kinematic equations, specifically V = Vo + at and Y - Yo = Vo*t + 0.5*a*t², to determine the time and initial speed of the second stone.

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  • Understanding of kinematic equations in physics
  • Knowledge of free fall acceleration and gravity (9.8 m/s²)
  • Ability to solve quadratic equations
  • Familiarity with the concept of initial and final velocity
NEXT STEPS
  • Study the kinematic equation Y - Yo = Vo*t + 0.5*a*t² in detail
  • Learn how to apply the concept of relative motion in physics problems
  • Explore the effects of initial velocity on projectile motion
  • Practice solving similar free fall problems with varying initial conditions
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Students studying physics, particularly those focusing on kinematics and free fall motion, as well as educators looking for examples of real-world applications of these concepts.

sona1177
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Homework Statement


A rock climber stands on top of a 50-m-high cliff overhanging a pool of water. He throws two stones vertically downward 1.0 s apart and observes they cause a single splash. The initial speed of the first stone was 2.0 m/s.

a) How long after the release of the first stone does the second stone hit the water?
b) What was the initial speed of the second stone?
c) What is the speed of each stone as they hit the water?

Homework Equations


V = Vo + at
Y - Yo = volt + .5at2
v2 = vo2 + 2a(Y - Yo)
Y - Yo = .5(Vo + V)t

The Attempt at a Solution


The problem I am having is that I don't know how to take account the time difference. For instance, you are not just solving for t but have to take into account that one was dropped 1 second after the other. For the first stone, I calculated a time of 2.98 seconds using formula Y - Yo = volt + .5at2
Y=-50 m
Yo=0m
Vo=-2 m/s
t=?
ay=-9.8 m/s^2

Label Axis: I am assuming the up direction is positive and down direction is negative.

I can't proceed to parts B and C until I know A. Please Help! Thank you very kindly.
 
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A single splash is seen, hence they hit the water at the same time. Thus, given the initial velocity of the first stone, and the acceleration due to gravity, how long does it take for it to hit the water?

For b, if it is to cover the same distance in the time it takes a - 1second, what must that stone's initial velocity be?
 
sona1177 said:
For the first stone, I calculated a time of 2.98 seconds
So, you solved it :)

a) Because both stones splash at the same moment - the second stone hit the water 2.98s after the release of the first stone.
 
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