Physics Homework Help (acceleration & velocity)

  • Thread starter Kiwi
  • Start date
  • #1
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Hello,

I was wondering if anyone could help me with the following question:

How long does it take for a shoe to drop 75 m from rest? What is the final velocity?

I have that the acceleration is equal to gravity at -9.8 m/s squared and that the distance is 75 m and the intial velocity is zero but I can't get much further than that. Thanks very very much for your time! :smile:
 

Answers and Replies

  • #2
Pyrrhus
Homework Helper
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Kiwi said:
Hello,

I was wondering if anyone could help me with the following question:

How long does it take for a shoe to drop 75 m from rest? What is the final velocity?

I have that the acceleration is equal to gravity at -9.8 m/s squared and that the distance is 75 m and the intial velocity is zero but I can't get much further than that. Thanks very very much for your time! :smile:

Look up kinematic equations
 
  • #3
Simfish
Gold Member
818
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y = 75 - 4.9t^2.
Solve for y = 0.
 
  • #4
Tide
Science Advisor
Homework Helper
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We're all waiting for the other shoe to drop! (Sorry - couldn't resist!)

BTW - I think air drag will be an important factor in this one but I'm sure your textbook isn't interested in that complication.
 
Last edited:
  • #5
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Yea, in most High School Physics text, air resistance is neglected.
 
  • #6
(Vf)^2=(Vo)^2+2ad

Vf=Final Velocity
Vo=Initial Velocity
a=Acceleration
d=Distance

*This equation does not include air drag
 
  • #7
193
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ya just use the equation mentioned above and you should be able to get the right awnser. :approve:
 
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