What's the equation for calculating when an object will hit the floor?

Question

It's something about.. -16m or... something strange.. I forgot the word for this too...

Answer 1

h = h0 - 16t^2, with h0 = initial height, when h is in feet and t is in seconds.
So, for h to be 0 (it hits the floor),
h0 = 16t^2
h0/16 = t^2
(sqrt h0)/4 = t
This equation applies for a compact body falling over a short distance close to the earth, so that air resistance is negligible and gravity can be considered constant.
If you want to include air resistance the equation is more complicated.
For a general discussion of these formulas in metric units as well as English units, and a discussion of falling further away from the earth, for example, orbits and escape velocity, see
http://en.wikipedia.org/wiki/Equations_for_a_falling_body
http://hypertextbook.com/physics/mechanics/falling/index.shtml
For a discussion of falling bodies with air resistance considered, see
http://www.lerc.nasa.gov/WWW/K-12/airplane/falling.html

Answer 2

x = g*t^2/2

where x is the distance an object falls over a time t.

For example, an object falling for t = 3 seconds would travel x = 32 ft/s^2 * 9 s^2 / 2 = 144 feet. (Note how the units multiply together: ft/s^2 * s^2 = ft.)

Answer 3

first you have to know how the object will fall. linear fall motion or projectile fall motion.

a) for a linear motion;
s=l + ut + 0.5gt^2
v^2=u^2 + 2g(h - l)
v=u + gt
**s=displacement. l=initial displacement. u=intial velocity. g=gravitational constant. t=time taken. h=height. v=final velocity.

b) for a projectile motion;
still going to use the equation that i've mentioned ealier. but in 2D form - x axis and y axis. you have to draw out the axis for the fall motion in x and y axis. most important parameter that you need to know or find first is the time taken, t. coz time is the only constant that same for both axis (g are for y axis but x axis didn't use g). so you only can use the time as a parameter to relate the x and y axis motion equations.

*please refer to dynamic books for a better understanding. the previous equation from all the previous answerer gave the correct equations too. but these equations i gave is the complete one for university studies. i really hope that i can help. not to help you to understand it but to help you become more interested with it.

Answer 4

s = ut +1/2 a multiplied by t squared . a = g (for gravity) = 9.8m/sec/sec. u = 0, so, ut = 0. then 16 = 9.8 multiplied by t squared divided by 2. you do it now!(answer = approx 1.8sec)

Answer 5

gravity is causing it to head towards the floor at 9.8 meters per second per second. so you figure it out from there. i don't know the equation but i know how gravity causes things to fall.

Answer 6

here's a great site with all the equations of motion listed...

http://en.wikipedia.org/wiki/Equation_of_motion

Answer 7

s=at