Duration of Fall

The Object Time to Drop formula computes the approximate  Time to drop time (t)  it would take an object to free fall from the height (h). 

INSTRUCTIONS: Choose the preferred units and enter the following:

• (h)  This is the height.

Fall Time (t): The calculator return the approximate time in seconds.  However, this can be automatically converted to other time units  via the pull-down menu.

Related Items:

• Distance travelled under constant acceleration
• For a simple video on how this calculator is used, CLICK HERE.  
• computing the height of an elevation based on angles and measurements.

Description

The formula for the height of a fall is:

• h = ½•g•t²

Solving for t we get:

`t = sqrt(2h/g)`

This is a simplification of the general formula of distance travelled under constant acceleration:

• d =  x + v•t + ½•a•t²

where: 

• x is the initial distance
• v is the initial velocity
• a is the constant acceleration 

For distance travelled in a fall, x is zero, v is zero and a is g - acceleration due to gravity in our example).  This formula does not account for the effects of air resistance (force of drag).

Use a stopwatch to measure the time it take for a heavy object to drop from the top of an object to the bottom.  This formula will provide the approximate height based on that measurement in time.  This formula does not take into account the effect of air friction, but a heavy smooth object has relatively little effect.  Also, make sure that the object is dropped over the side with no initial up or down motion since that will affect the time of drop.