Changes in charge, current and potential difference during the charging and discharging of a capacitor are all exponential-type behaviours. Specifically, the current that transfers charge to or from a capacitor (during charging or discharging respectively) is always greatest at first and declines to zero as time increases. During discharging, the charge loss and the drop … Continue reading Charging a Capacitor (analysis)
Aircraft take-off velocity
Three years ago I explained how to use photographs to estimate the speed of a passing car. You can read that article at https://physbang.com/2020/08/02/keep-the-cogs-turning/. Now it is time to use a similar technique to answer a more challenging question: what is the take-off velocity of a passenger jet? Of course, the answer could be found … Continue reading Aircraft take-off velocity
Measuring Speed
This is the third part of a mini-series looking at motion and here we’ll be considering different ways to measure speed as well as some common sources of error. In theory, speed is easy; we just need a distance (measured using a ruler, for example) and a time (probably measured using a stopwatch but ideally … Continue reading Measuring Speed
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