Help with a confusing free-fall motion physics problem?

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SUMMARY

The discussion revolves around solving a physics problem involving free-fall motion, specifically the simultaneous dropping of two rocks from a building. West drops a rock, and 1.25 seconds later, Lindsay throws her rock downward at a velocity of 28.0 m/s. The key equations used are the kinematic equations for motion under gravity, particularly y = y0 + v0(t) - 1/2(g)t². The confusion arises regarding the setup of Lindsay's equation, particularly the sign of the initial velocity and the total time of descent.

PREREQUISITES
  • Understanding of kinematic equations in physics
  • Knowledge of free-fall motion and gravitational acceleration (g = 9.81 m/s²)
  • Ability to manipulate algebraic equations
  • Familiarity with the concept of vectors in physics
NEXT STEPS
  • Study the kinematic equations for one-dimensional motion
  • Learn how to analyze free-fall problems using initial velocity and time
  • Explore the concept of vector direction in physics problems
  • Practice solving simultaneous motion problems in physics
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This discussion is beneficial for physics students, educators, and anyone seeking to understand the principles of free-fall motion and kinematic equations.

Jrohazn
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I'm taking physics for the first time, and I've been attempting the textbook problems, but I can't seem to get it.

1. West stands on the roof of a building, leans over the edge and drops a rock. Lindsay waits 1.25 s after West releases his rock and throws her own rock straight down at 28.0 m/s. Both rocks hit the ground simultaneously. Calculate the common height from which the rocks were released.
2. y=y0+vo(t)-1/2(g)t^2
I'm honestly not even sure how to do it. For Wes: 0=y0-1/2(g)t^2; y0=1/2gt^2
I'm confused on how to set up Lindsay's equation. I checked other people's answers on chegg, and they seem to set up vo as a positive vector, but I thought that since she's throwing down, that it would be negative? Can someone clear that up for me? And for time, would it be (1.25+t)?

Please help :(
 
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I suggest you do not look at other people's answers and try to solve it yourself by thinking instead.

How would you set up the equation that determines how long it takes for Lindsay's rock to hit the ground?
 

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