Sept. 19 – Kinematic Equations

On Friday I showed you where the 5 kinematic equations come from.

Here is your long awaited formula sheet!

• Formula Sheet

Here are the notes:

This chart is on page 54 in your textbook.  It shows the relations between these 5 equations and the 5 variables.

Example: A light bulb drops from a 3 m ceiling and falls to the floor.  How long does this take?  (Acceleration due to gravity is 9.81 m/s²).

Given: ∆d = 3m [down]        vi = 0 m/s [down]      a = 9.81m/s² [down]

Required: ∆t

Analysis: The third equation contains all these variables.

∆d = vi ∆t + 1/2 a (∆t)²

Solve: ∆t = 0.78 s

Statement: The light bulb takes 0.78 s to fall to the ground.

We then tested it by dropping stuff from the ceiling and got surprisingly accurate results!

Homework

You can now do the homework from day 7 and 8 of the Unit Outline.