Free Falling Pebble

**String (S _{i}P_{j}A_{jk}) = S_{7}P_{5}A_{51} Base Sequence = 12735 String Sequence = 12735 - 5 - 51 **

Expressions Of Pj Problems

Free Falling Pebble - Calculating Speed Of Free Falling Body

Math

(a) What is the speed of a pebble 4 secs after it is dropped?

(b) What is the average speed during the 4 secs?

(c) At what instant does the pebble actually posssess this average speed?

**The string**: S_{7}P_{5}A_{51} (physical change - speed).

{m_{i}} = {pebble, dropper, air}

S_{i} = air containing pebble, space conting dropper
*Independent Pj Problem (IPP)*: air *containership*,

*Dependent Pj Problems (DPP)*: *identity* (of dropper), *force* (of dropper),

*Pj Problem of Interest (PPI)* is *change* (speed, velocity, acceleration,instantaneous time and duration are *change* problems).
**The math**:

1(a) The speed v, of a free falling object on earth where the acceleration due to gravity is constant at 32 ft/sec^{2}
* = 32t* (where t is time in secs).

So at t = 4secs, the speed v = 32 x 4 = 128ft/sec.

(b) Distance d, = *16t ^{2}*.

So, average speed = (16 x 16)/4 = 256/4 = 64 ft.

Average speed occured at t=2s; since v(2) = 64.

in geral average speed occurs in t/2 secs.