Calculating Total Time and Height of a Free-Falling Object

[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.

thanks in advance

 

[tiny-tim]

hi thomasxc!

if the total time is T, apply the standard constant acceleration equations at t = T and t = T - 1

 

[thomasxc]

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.

 

[tiny-tim]

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

 

[thomasxc]

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

Im lost as to how to set that up.

 

[tiny-tim]

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

noooo

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

 

[iRaid]

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

 

[cupid.callin]

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.