Max height, freely follwing question

[georgelopez00]

A certain freely falling object requires 1.5s to travel the last 30.0 m before it hits the ground. from what height above the ground did it fall?
The answer is 32.8 m but i don't no how to get it. please help

 

[loonychune]

You have to at least have a go at the question or say what you think you MIGHT DO or perhaps what equations might be relevant... for all I know I might have spent as much time writing this reply as you have spent on the problem

 

[georgelopez00]

You have to at least have a go at the question or say what you think you MIGHT DO or perhaps what equations might be relevant... for all I know I might have spent as much time writing this reply as you have spent on the problem

i used the equation v=at+inital velocity. i figured the velocity is 0 m/s so i got the inital velocity as 14.7 m\s

 

[loonychune]

Let's try to rethink the problem.

You have an object that is released from some height we do not know (32.8m according to your answer).
It travels for some length of time greater than 1.5 seconds.
During the FINAL 1.5 seconds it travels 30m.

You did not state in the question, but I'm assuming that the object is released from REST (i.e. when at the height 32.8m).

Now you know a few different variables in a couple of equations for different parts of the journey. Then it's a matter of solving simultaneous equations.

See this post, a very similar problem:

https://www.physicsforums.com/showthread.php?t=252886