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Very hard problem

  • Thread starter nemzy
  • Start date
126
0
A flowerpot is knocked off a balcony 18.0 m above the sidewalk heading for a man of height 1.85 m standing below. How high from the ground can the flowerpot be after which it would be too late for a shouted warning to reach the man in time? Assume that the man below requires 0.300 s to respond to the warning. Take the speed of sound in air to be 343 m/s.


ok, so y=(1/2)gt^2 since there is no initial velocity

but thats all i know, i have no idea how to solve this type of problem

thx
 

Zurtex

Science Advisor
Homework Helper
1,120
1
You don't know where the person is so I presume they expect you give an estimate, I would go with something like 20 metres (or just choose a dummy variable if you want), work out how long the sound takes to get there and add the reaction time.

Then work out the time it takes the flowerpot to hit this man using

y = 18 - 1.85 (the distance from the ledge to the man)

Once you have this time, minus the time you worked out above then plus this back in to the formulae and you have your answer.

Wow I feel like I am back in my AS level Physics class again lol.
 

jamesrc

Science Advisor
Gold Member
476
1
I would assume the person who knocked the flower pot over is the one who will shout the warning. So you find the minimum time before impact by adding the reaction time to the time it takes the sound to travel (18-1.85)m. Then just think about it the way Zurtex described it.
 

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