# Free-falling object question

## Homework Statement

an object falls .48 of the total distance in the last one second of its fall. determine total time and height from which it was dropped

## Homework Equations

I have no idea. The kinematics, possibly?

## The Attempt at a Solution

I have no idea where to begin. Ive tried guess and check with the kinematic equations, to no avail. Please help.

thanks in advance

## Answers and Replies

tiny-tim
Science Advisor
Homework Helper
hi thomasxc! if the total time is T, apply the standard constant acceleration equations at t = T and t = T - 1 I'm so rusty at all of this. This is on an intro for my physics class. I am totally lost. I dont have distance, initial or final velocities, only acceleration, T and T-1.

tiny-tim
Science Advisor
Homework Helper
I dont have distance, initial or final velocities, only acceleration, T and T-1.

you do have the initial velocity, it's zero

you also know that s at time t = T-1 is 0.52 times s at time t = T

ok. so for displacement, T-1=(.52)t right?

Im lost as to how to set that up.

tiny-tim
Science Advisor
Homework Helper
ok. so for displacement, T-1=(.52)t right?

noooo get some sleep, read the question, and try again in the morning :zzz:

v=d/t, with that you'll have the velocity at t=1s... Does that help?

I just worked out your problem and you can use s=ut + (at^2)/2 at t=t and t=t-1.

just write 2 eqns and you'll figure out a way easily.