A ball is dropped from the top of a building...

  • #1

Homework Statement


A ball is dropped from the top of a building and falls vertically downwards. Air resistance can be neglected. After falling a distance d, the speed of the ball is v. Determine the speed of the ball (in terms of v) when it has fallen a distance of 2d.

Homework Equations




The Attempt at a Solution


We tried to isolate for V2 and d and then substitute them into each other but that didn't work. Please help!
 

Answers and Replies

  • #2
FactChecker
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You should show the relevant equations and what you did with them in your work.
 
  • #3
You should show the relevant equations and what you did with them in your work.
I'm sorry but whats a relevant equation? a=9.8m/s2 and V1=0m/s and I'm not sure what to put for d and V2 which is what we are solving for. Not sure if that helps?
 
  • #4
vela
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Can you identify what kind of problem this is, e.g., what concepts are relevant? What do you mean by "university acceleration" in the title? You're referring to ##d##, ##v_1##, and ##v_2##. The variable ##d## is defined in the problem statement, but we'd have to guess what you mean by ##v_1## and ##v_2##.
 
  • #5
Can you identify what kind of problem this is, e.g., what concepts are relevant? What do you mean by "university acceleration" in the title? You're referring to ##d##, ##v_1##, and ##v_2##. The variable ##d## is defined in the problem statement, but we'd have to guess what you mean by ##v_1## and ##v_2##.
Im sorry im in grade 12 doing a "University" question. I just wrote down what the question asked me. I have no clue what to do. Sorry
 
  • #6
PeroK
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Im sorry im in grade 12 doing a "University" question. I just wrote down what the question asked me. I have no clue what to do. Sorry
Hint: Distance is the area under a graph of speed against time.
 
  • #7
jbriggs444
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I'm sorry but whats a relevant equation? a=9.8m/s2 and V1=0m/s and I'm not sure what to put for d and V2 which is what we are solving for. Not sure if that helps?
We are given information on both the distance fallen and on the final velocity. From that information [and an assumption of constant acceleration] it is possible to write down an expression for the actual acceleration. That acceleration might not be 9.8 m/s2.

What are some equations that you know for motion under constant acceleration? Or for work, momentum and kinetic energy?
 

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