Wednesday, Sept 17, 2008 - Block 3

Collect RA 2.1

Quiz on Uncertainties

Seattle example for v = d/t, velocity is a rate.
Acceleration is a rate of a rate. It is how the velocity changes with time.

a = change in velocity/time interval = (vf -vi) /t
or
vf = vi + a * t

Example of a rate of a rate comparing hourly wage with yearly raise.
Examples of acceleration.
You can feel acceleration (slowing down, speeding up, turning) but you cannot feel constant velocity.

amount = initial amount + rate * time

Picket fence lab to measure acceleration near surface of Earth ~ 10 m/s/s

Examples calculating final velocity of an object dropped an falling for a given time.
Examples calculating final velocity of an object thrown down and then falling for a given time.
Included examples of throwing an object up.

On the way down, an object picks up speed at a rate of 10 m/s/s. On the way up, an object loses speed at a rate of 10 m/s/s.

In d = v*t, if the acceleration is constant, we can still use the equation if we use the average velocity for v. vavg = (vf + vi)/2

Several examples of calculating distance an object falls if it falls for a certain time or is thrown down and falls for a given time.
Examples of calculating displacement of an object if you throw it up.

Worksheets RA 2.2, 2.3, 2.4 due Thursday. Students had time to work on them in class.