# Free-falling object question

• thomasxc

## 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. I've tried guess and check with the kinematic equations, to no avail. Please help.

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 don't have distance, initial or final velocities, only acceleration, T and T-1.

I don't 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.

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.