Calculating Time and Velocity with a Spark Tape

[Nick A]

Well I used a spark timer and got a spark tape, but forgot how to use the spark tape to calculate time and velocity.
I think its something like the number of dots/60 to get time and v=d/t to get velocity
Am I right?

 

[berkeman]

What's a spark tape?

Sounds like you have the right idea, though.

 

[Nick A]

Spark Tape is the tape u insert into the spark timer

 

[mgb_phys]

I'm guessing it's like the ticker tape counters in school dynamics experiments.

You have a length of lightweight paper tape which attaches to the moving object and goes through a mains fed coil which taps a bit of carbon on the paper every 1/50 or 1/60 second to give a time-displacement relation. I suppose you could use a mains spark to burn marks on the paper rather than draw them.

Nick - The marks will be either 1/60s apart in USA/Canada or 1/50s in Europe.

 

[Nick A]

yea that was what we did, thx!

 

[berkeman]

Thanks mgb_phys, I'd never heard of that before.

 

[TVP45]

So, measure the distance between each spot. Make a chart. What does this represent?
What is the time between each spot? What made them? How are they related to the frequency of the power mains?
How can you manipulate (add, subtract, multiply, or divide?) those quantities to get velocity? What kind of velocity (average or instantaneous) do you think you have?
What else could you do with the velocities?