Solving the Egg-Throwing Problem: Seeking Help from Clair_A_Net

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The problem involves calculating the initial speed of an egg thrown vertically upward from a tall building, which reaches a point 50.0 m below its starting position after 5.00 seconds. Initial attempts using the equations of motion yielded incorrect results, with one calculation mistakenly omitting the square of time. The correct approach involves using the equation Xf = Xo + Vo*t + (1/2)a*t², where a is the acceleration due to gravity (9.8 m/s²). After correcting the time variable, the initial speed was determined to be -14.5 m/s, indicating the egg's upward velocity. Clarification on the calculations and assumptions was essential for arriving at the correct answer.
clair_a_net
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K. I was given the problem:

An egg is thrown nearly vertically upward from a point near the cornice of a tall building. It just misses the cornice on the way down and passes a point a distance 50.0 m below its starting point at a time 5.00 s after it leaves the thrower's hand. Air resistance may be ignored.

And I'm trying to find: What is the initial speed of the egg?

so i used the equation Xf=Vo*t+Xo ie: 50+Vo*5+0 getting 10 m/s, but that answer is wrong.

so then i tried Xf= Xo+Vo*t+(1/2)a*t^2 ie 50=0+Vo*5+.5*9.8*5 assuming a=9.8 but that wasn't given. i got 34.5 and that was wrong too. So if anyone has any idea as to what I'm doing wrong or how to get the correct answer let me know.

thanks
clair_a_net
ps if its after 12pm tonight then the homework was already due so thanks for trying anyways. but i would still like to know what I am doing wrong.
 
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clair_a_net said:
...

so then i tried Xf= Xo+Vo*t+(1/2)a*t^2 ie 50=0+Vo*5+.5*9.8*5 assuming a=9.8

...
You have,

50=0+Vo*5+.5*9.8*5

which I assume is just a typo (for the power of t = time) and that you actually used

50=0+Vo*5+.5*9.8*5²

this gives

50 = 5Vo + 122.5
5Vo = -72.5
Vo = -14.5 m/s
===========
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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