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Need help with calculating Gravitational Constant

  • Thread starter JohnDoeJD
  • Start date
  • #1
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Homework Statement



I would like some help with this question:

A bomb is dropped on a foreign planet. The bomb is dropped from a height of 200m. The bomb traveled the last 100m of the fall in 2.5 seconds. What is the acceleration from the gravitational constant on this planet?


2. The attempt at a solution

I tried making two seperate equations, one for the total fall (200m) and one for the 100m fall and combining them but I couldn't get anything because I had too many variables.
 

Answers and Replies

  • #2
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What is the acceleration from the gravitational constant on this planet?
do you mean "and" ?
 
  • #3
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Yes, that's what I meant sorry.
 
  • #4
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write s = ut + .5 at^2 for (t - 2.5) and t seconds
t it the total time of fall

substract 2 eqn's and substitute st - st - 2.5 = --- ???
 
  • #5
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Yes, that's what I meant sorry.
gravitational constant remains same everywhere

thats why it is called "UNIVERSAL" gravitational constant !!!!!!!

EDIT:

confirm it yourself by finding its value in this question
 
  • #6
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write s = ut + .5 at^2 for (t - 2.5) and t seconds
t it the total time of fall

substract 2 eqn's and substitute st - st - 2.5 = --- ???
I did that originally but I couldn't figure out how to isolate A. This is what I had:

100 = 0(t) + 0.5at^2 - 0(t-2.5) + 0.5a(t-2.5)^2
 
  • #7
1,137
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rearrange this eqn to a simpler form

use another eqn: 200 = .5at^2

use this eqn to subs. t in first eqn
yu'll get something in √a and a

consider √a as y and and a as y^2 and solve this just like a quadratic eqn!!!
 
  • #8
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Thank you.
 
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