Analysis of VideoLogged data
VisiLog can now capture frames rapidly (recording data from sensors frame by frame as well). We have been using this ability - together with analysis of the data by Datadisc 32 - to develop new and more direct ways to demonstrate the fundamentals of dynamics.
First a toy car free-wheeling down a ramp. VisiLog allows you to trace the movement and creates X and Y data channels:
Good quadratic fits are obtained and the acceleration in the two directions can be quickly derived.
How about the classic falling (and bouncing ball)?
VisiLog can trace the fall and bounce to create the data
Datadisc 32 fits the curve and returns a value for 'g' of 9.82 ms-2.
Bouncing ball filmed with a domestic camcorder set
to high speed shutter to freeze motion of ball
Now for conservation of momentum
VisiLog records an elastic collision between two trolleys on an air-track:
The trace facility allows us to follow the first trolley (shown in the VisiLog graph above). The second trolley can be followed as well and Datadisc 32 assembles all the data and computes straight line fits:
A similar process for the case where the trolleys stick together:
Here the change in velocity can be related to the mass before and after collision:
Mass before collision = 410.35g
Channel 2: Distance (X) / mm, Linear fit of
channel 6 against channel 8.
Channel 6: Distance (X) / mm, Data from VisiLog
Mass x velocity after collision = 195 x 0.82218 = 160 N s