ISO instructions for acceleration apparatus, or lesson plans

[arosinblum]

Hey folks, I came across a box of these things "https://us.vwr.com/store/product/16907766/acceleration-timer"

they didn't come with a set of instructions or lesson plans. anyone have experience with these that may have a lesson plan or set of instructions I could use? thanks!

 

[Ibix]

I would imagine that if you plug it in the little pin will start hammering at 60Hz (or whatever your mains AC frequency is). The discs are presumably inked, and the hammering will print a dot on the paper tape. If you attach the tape to something moving away from the instrument it'll pull the tape through it and the distance between the dots will be the distance it travelled in 1/60 seconds. So multiply the distance between dot 1 and dot 2 (in meters) by 60 and you'll get the speed at time zero (in meters per second). Ditto the distance between dot 2 and dot 3 and you get the speed at time 1/60 s. Keep going and plot the speed as a function of time and you have a v-t graph. You can integrate or measure the slope to get distance travelled or acceleration.

 

[berkeman]

Welcome to PF.

anyone have experience with these that may have a lesson plan or set of instructions I could use?

Yikes. Whatever you attach the end of the tape to must have sufficient mass to not be affected by the drag of the tape, in order to not affect the acceleration being measured. So it wouldn't work well for a small "Pinewood Derby" car-down-ramp type experiment. You could maybe attach it to the belts of a couple kids running a short race or something...

 

[jrmichler]

Yup, that's exactly the device I remember from high school physics class. Ours was made interesting because it was a new high school where the physics lab had a $20,000 power supply connected to all of the lab tables. The power supply was not regulated (?), so whenever one more buzzer was connected, all of the others slowed down. The teacher's work around was to swipe a deep cycle battery from the old high school and use the $20,000 power supply as a battery charger.

Just have the students attach a weight to the paper strip and drop it. Then turn the buzzer thing sideways so the tape runs straight through and teach about friction. The lesson plan is simple - tell them to run it, then do as in Post #2. The writeup should include a discussion of their measured value for acceleration compared to the published value, and why they differ. You might need to schedule a lecture on error sources in this experiment and how to deal with the errors.